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billygoat

18g Gorgonian Garden - A Caribbean Biotope

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billygoat
6 hours ago, Ratvan said:

I do love that Snail army shot

To be honest, when I first pulled those snails out of the shipping box and saw how many there were, I had a brief moment of hesitation. 😅 But I figure they are very small, have slow metabolisms, and are often active for just a few hours a day, so it's probably fine to have so many of them in there. Plus they stir up the sandbed a bit with their burrowing activities, so that's a nice bonus.

 

With those million dwarf Ceriths I also added a pair of Caribbean Nerite snails (I think they are either Nerita fulgurans or Nerita tessellata, or possibly one of each), which are the largest snails I've had so far. Previously I'd only kept the so-called "virgin Nerite" variety (Neritina virginea), which are much smaller and more active, so it's interesting to compare the two types. I've read stories about Nerite snails crawling out of the water and exiting the aquarium, but so far I have not seen this happen with either variety in my tank. The smaller virgin Nerites have no interest in leaving the water, and the larger species park themselves right on the water line when they are resting. Virgin Nerites are active all of the time and stop to rest only infrequently, but the larger snails have so far been active only at night.

 

Nerites are probably not the most effective grazers around, but I think they are an interesting addition that helps to diversify my clean-up crew. ☺️ They are a common sight on rocky shorelines and in tide pools throughout the Caribbean.

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Amphrites

Just to contribute some additional experience, my nerites like to take upside down trips across the bottom of my lid or try to get into the back chambers of my tank. They are inter-tidal species so they absolutely may eventually go carpet surfing on you, really glad to hear they haven't yet though, hard to say what any animal will do in our systems lol.

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Ratvan

My cats love it when I have nerite snails. You can hear them happily chirping at them shortly before the "crunch" sounds

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billygoat

I'll definitely keep an eye on the Nerites to make sure they don't go on any strange dry-land adventures. I have a feeling that it's only a matter of time! 😄

 

I got home a bit early from work today. It's always nice to be able to observe my tank under midday lights. Cyanobacterial growth continues but not at an especially worrying pace; I am easily able to keep it under control manually.

 

IMG_0377.thumb.JPG.0b762d780969cf2fdc777d6a3db7e527.JPG

 

The frequent turkey basting seems to please my porcelain crabs as well. They are getting used to me walking around the aquarium, but they aren't quite accustomed to my phone up against the glass. Most of my pictures end up with just a claw poking out of the rock, kinda like this:

 

IMG_0376.thumb.JPG.1b0721b8f0940d34f64e948227397f91.JPG

 

It's still super cool to watch them though. I love those crabs. 😊

 

 

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Amphrites

"Go away I'm feeling crabby =("

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billygoat

Alright so, since I have the whole afternoon to do nothing but stare at my tank, it's time for nerd talk.

 

For some time I have noticed gas bubbles forming spontaneously deep in my aquarium's sandbed. At first I believed these were associated with the subsurface layer of cyanobacteria that has established itself up against my glass. It made sense that the cyanobacteria would be producing bubbles of oxygen as it performed photosynthesis throughout the day. However it recently came to my attention that many of the bubbles in my substrate have no apparent connection to photosynthetic activity. They form all over the place, including in some areas that are downright dark. I therefore believe that rather than being the products of simple photosynthesis, these bubbles are instead evidence of the phenomenon of denitrification.

 

IMG_0378.thumb.JPG.62368689402cca19f607c1a66ce85460.JPG

 

Most reefers know about nitrification (or the "cycle", as it is commonly known) - the process by which various bacteria take toxic ammonium and turn it into nitrite and then into nitrate, effectively converting some of the most toxic substances in our aquariums into much less dangerous compounds - and take pains to establish healthy populations of nitrifying bacteria before adding livestock to their tanks. Denitrification is perhaps somewhat less widely understood, probably because unlike nitrification it does not occur in all home aquaria (or even in most, if I had to guess). Denitrification usually takes place only in zones of the aquarium where the oxygen concentration is very low, such as inside of deep, undisturbed layers of substrate. The bacteria living in these regions take nitrate out of the water and convert it into nitrogen and oxygen gas, effectively removing it from the system. I believe that the bubbles that I see in my substrate are probably evidence of this phenomenon in action.

 

So when I put some flakes or pellets in my tank, the fish and other organisms in my aquarium eat that food and digest it, producing ammonium compounds which are converted into nitrites, which are converted into nitrates, which are then captured and split into nitrogen and oxygen gas, which then leaves my tank. I put flakes in and my aquarium turns them into air. Insane. I know this is a simple thing that happens all over the world every day, but it just floors me to think that this whole cycle is taking place right in the tiny box of water in my living room. This hobby can be so humbling sometimes.

 

Denitrification, incidentally, also probably helps to explain why my nitrates consistently test very low these days, despite the fact that I have ratcheted up feedings quite a bit! Well, that and the fact that my Ulva is a ravenous nutrient sponge.

 

IMG_0379.thumb.JPG.b4cada16879d4da0ca530d9f8b8b3a17.JPG

 

Speaking of Ulva, I may end up further reducing the photoperiod on the 'fuge to try and get it to grow a bit slower. The only reason I really wanted a refugium was to provide pods with a safe space to reproduce (and I am happy to report that they are indeed reproducing prolifically), but it turns out that Ulva is very good at sequestering nutrients regardless of what you think you are using it for. 😅

 

Okay, sorry for the term paper here! Thanks for reading, fellow reefers! 😂

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Kangster911

My understanding was that you needed a deep sand layer (3"+?) for these anabolic bacteria colony to thrive. How deep is your sand? If it indeed was denitrification in your tank, it would be really awsome. 

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mitten_reef
23 minutes ago, billygoat said:

Alright so, since I have the whole afternoon to do nothing but stare at my tank, it's time for nerd talk.

 

For some time I have noticed gas bubbles forming spontaneously deep in my aquarium's sandbed. At first I believed these were associated with the subsurface layer of cyanobacteria that has established itself up against my glass. It made sense that the cyanobacteria would be producing bubbles of oxygen as it performed photosynthesis throughout the day. However it recently came to my attention that many of the bubbles in my substrate have no apparent connection to photosynthetic activity. They form all over the place, including in some areas that are downright dark. I therefore believe that rather than being the products of simple photosynthesis, these bubbles are instead evidence of the phenomenon of denitrification.

 

IMG_0378.thumb.JPG.62368689402cca19f607c1a66ce85460.JPG

 

Most reefers know about nitrification (or the "cycle", as it is commonly known) - the process by which various bacteria take toxic ammonium and turn it into nitrite and then into nitrate, effectively converting some of the most toxic substances in our aquariums into much less dangerous compounds - and take pains to establish healthy populations of nitrifying bacteria before adding livestock to their tanks. Denitrification is perhaps somewhat less widely understood, probably because unlike nitrification it does not occur in all home aquaria (or even in most, if I had to guess). Denitrification usually takes place only in zones of the aquarium where the oxygen concentration is very low, such as inside of deep, undisturbed layers of substrate. The bacteria living in these regions take nitrate out of the water and convert it into nitrogen and oxygen gas, effectively removing it from the system. I believe that the bubbles that I see in my substrate are probably evidence of this phenomenon in action.

 

So when I put some flakes or pellets in my tank, the fish and other organisms in my aquarium eat that food and digest it, producing ammonium compounds which are converted into nitrites, which are converted into nitrates, which are then captured and split into nitrogen and oxygen gas, which then leaves my tank. I put flakes in and my aquarium turns them into air. Insane. I know this is a simple thing that happens all over the world every day, but it just floors me to think that this whole cycle is taking place right in the tiny box of water in my living room. This hobby can be so humbling sometimes.

 

Denitrification, incidentally, also probably helps to explain why my nitrates consistently test very low these days, despite the fact that I have ratcheted up feedings quite a bit! Well, that and the fact that my Ulva is a ravenous nutrient sponge.

 

IMG_0379.thumb.JPG.b4cada16879d4da0ca530d9f8b8b3a17.JPG

 

Speaking of Ulva, I may end up further reducing the photoperiod on the 'fuge to try and get it to grow a bit slower. The only reason I really wanted a refugium was to provide pods with a safe space to reproduce (and I am happy to report that they are indeed reproducing prolifically), but it turns out that Ulva is very good at sequestering nutrients regardless of what you think you are using it for. 😅

 

Okay, sorry for the term paper here! Thanks for reading, fellow reefers! 😂

Be very careful.  While the denitrification process sounds exciting, it could also be ammonia pocket (ammonia is gas).  I had a tank with 2” sand bed that I didn’t clean up for a while, then one day the whole system went spiraling out of control once the sand got disturbed.  I couldn’t soak up nitrate fast enough.  One reason many people on NR advised on cleaning the sandbed regularly. 

Again, don’t mean to scare you, but be very careful. 

 

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Amphrites
23 minutes ago, Kangster911 said:

My understanding was that you needed a deep sand layer (3"+?) for these anabolic bacteria colony to thrive. How deep is your sand? If it indeed was denitrification in your tank, it would be really awsome. 

You can and probably do have denitrification happening on live rock, tons of types of media can facilitate it as well, there are even reactors for sulfur-doped media which will de-nitrify en-masse for your system. DSB refugiums, when properly maintained, can take up an impressive amount of nitrate and anaerobic conditions really, really help (such as those found in DSB's).

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billygoat
18 minutes ago, mitten_reef said:

Be very careful.  While the denitrification process sounds exciting, it could also be ammonia pocket (ammonia is gas).  I had a tank with 2” sand bed that I didn’t clean up for a while, then one day the whole system went spiraling out of control once the sand got disturbed.  I couldn’t soak up nitrate fast enough.  One reason many people on NR advised on cleaning the sandbed regularly. 

Again, don’t mean to scare you, but be very careful. 

 

This is certainly a good thing to be aware of! I was not even aware that gaseous ammonia could accumulate down there. What could be producing ammonia in the sandbed, I wonder? My sand has never been cleaned or disturbed, so I'm quite interested in what's going on deep inside.

 

Now you've got me curious; I kind of want to stir up a portion of the sand and see if I get an ammonia spike. That's probably ill-advised so I will refrain from doing so, but it would make for an interesting experiment. 😄

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billygoat
33 minutes ago, Kangster911 said:

My understanding was that you needed a deep sand layer (3"+?) for these anabolic bacteria colony to thrive. How deep is your sand? If it indeed was denitrification in your tank, it would be really awsome. 

I should mention: the sand in the tank is about 2 inches deep on average. 

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Wonderboy

It's okay to disturb small areas - it would be interesting to see if anything fluctuated. Small disturbances will only introduce inhabitants to slight environmental changes and help make them "stronger". It often occurs naturally - such as, my pistols will occassionally move several cups of sand around.

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billygoat
5 minutes ago, Wonderboy said:

It's okay to disturb small areas - it would be interesting to see if anything fluctuated. Small disturbances will only introduce inhabitants to slight environmental changes and help make them "stronger". It often occurs naturally - such as, my pistols will occassionally move several cups of sand around.

Maybe tomorrow I will get in there and stir a few of those bubbles up into the water column, just to see what happens. I do have quite a few burrowing animals in my aquarium that are mixing things up on a small scale continuously (including a few worms, planarians, and other deep-delving creatures that I see crawling about and making burrows even towards the bottom of the sand) but I have not had any measurable ammonia for a long, long time. Then again I don't really test for it very often, so it's possible that levels have been fluctuating without my noticing. Seems like there would be more available nitrate if that were the case though. 🤔

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Amphrites

You probably should agitate it every once in a while, small areas at a time, as ammonia gas isn't the only byproduct various sulfides and other nasty and toxic gases can build up. Deep sand beds had/have a bad rep for crashing tanks when disturbed even slightly after a few years, that said 2 inches isn't actually deep.

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billygoat
2 minutes ago, Amphrites said:

You probably should agitate it every once in a while, small areas at a time, as ammonia gas isn't the only byproduct various sulfides and other nasty and toxic gases can build up. Deep sand beds had/have a bad rep for crashing tanks when disturbed even slightly after a few years, that said 2 inches isn't actually deep.

I have heard a whole lot of mixed stories about sandbeds; some seem to think they are fine and beneficial and others seem to think they are time bombs that will eventually explode and destroy your aquarium. Most aquarists appear to be somewhere in between. The depth of my sand (only 2 inches) seems like it is actually fairly standard, which leads me to wonder if denitrification may not be taking place down there after all, especially close to the surface where some of those bubbles are located. I think a cool experiment would be to disturb some of the sand that is in the middle of the tank, away from the glass. If air bubbles arise from the disturbed area I can probably be confident that some sort of anaerobic process is at work, and if they don't it's likely that the bubbles against my glass are in fact the products of photosynthesis.

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YHSublime

Without agitation I would worry with time

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Amphrites

I mean, it's hard to tell, I think Ratvan had some anaerobic activity in his shallow Pico tank sandbed. Your tank also likely has denitrifying bacteria all throughout it already anyway and I'm not sure two inches is dangerous, old-school plenum-attempts which reached 6+ inches deep, they could kill tanks. Or not... Don't have anything to go on but stories and a rough grasp of the science and chemicals which can be produced in such conditions, I'm sure most worked out just fine and yours isn't really deep anyway lol. 

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billygoat

Thanks for all the input folks, you've all really got me thinking. It would be very difficult to stir up my sand because of the way the tank is set up (unless I wanted to move a whole lot of rocks, rubble, rooting macroalgae, and various sessile creatures out of the way), so I will probably just leave it alone for the time being and hope that things work out for the best. After reading a lot today about sand and the problems it can cause I am sort of worried though! It seems that weird gas bubbles down there could either be fairly good or very bad... and there's no way of finding out which is the case without potentially screwing things up big time! 😥

 

If I see any black metallic deposits of hydrogen sulfide forming down under the sand I will definitely take some action, but for the time being I think I had better just play it safe and continue to observe. I have faith in the diverse benthic fauna that I've been able to collect so far; hopefully they will do the good work and keep that sandbed healthy!

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Ratvan
3 hours ago, Amphrites said:

I mean, it's hard to tell, I think Ratavan had some anaerobic activity in his shallow Pico tank sandbed. Your tank also likely has denitrifying bacteria all throughout it already anyway and I'm not sure two inches is dangerous, old-school plenum-attempts which reached 6+ inches deep, they could kill tanks. Or not... Don't have anything to go on but stories and a rough grasp of the science and chemicals which can be produced in such conditions, I'm sure most worked out just fine and yours isn't really deep anyway lol. 

Yeah I set of the H2S (Hydrogen Sulphide) alarms at work removing the sand bed. I had a dark grey strata within the sand. Bubbles sat on top of this. It was only 1.5-2" deep.

 

Before that I didnt stir the sandbed so...

 

I was popular in the office that day 😁

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TatorTaco

Just a thought, but if you wanted to stir up the sandbed a bit without moving corals, you could just blast the sand a bit with a turkey baster. That’s what I do. 

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billygoat
6 hours ago, Ratvan said:

Yeah I set of the H2S (Hydrogen Sulphide) alarms at work removing the sand bed. I had a dark grey strata within the sand. Bubbles sat on top of this. It was only 1.5-2" deep.

Crazy! Based on what I have read, there seem to be a few key takeaways regarding the formation of hydrogen sulfide in the sandbed:

  • It's important to ensure that no organics are buried in the sand, especially not under the rock. Decaying organic material on the underside of uncured live rock is a common catalyst for the generation of hydrogen sulfide.
  • Fine sandbeds appear to be more prone to the formation of sulfide deposits than coarser ones, probably because there is less water movement through the sand. Deep layers of fine-grained substrate such as oolitic sand are at the highest risk.
  • Water movement through and over the sandbed seems to be the single most important factor at play in preventing the formation of sulfide deposits. The author of this excellent article on hydrogen sulfide in home aquaria reports that he operated a reef tank for ten years with no issues (1-2 inches fine oolite as substrate), then decided to break his system down to upgrade. When he did this he removed his sand and placed it in a bucket in his garage. There was no smell and no evidence of metallic deposits upon removal, but after sitting in a bucket with no circulation for two weeks the sand was grey in color and reeked strongly of sulfur. This seems to suggest that proper circulation is critical to ensure the long-term health of the sand.
  • Benthic microfauna likely play an important role in maintaining the health of a deep sandbed, as their burrowing activities create passageways for water to move throughout the sand, ensuring that the microbes that live there are supplied with oxygen. Anoxia is a precondition for the formation of hydrogen sulfide.

This information leads me to wonder quite a bit about what is going on in my own sand, as it has sat almost undisturbed for nearly eight months now. There's a chance that the microbes down there are up to no good, but my instinct is to simply leave things alone. The tank looks good as it is, so perhaps it is best not to go poking around too much until I have a reason to suspect that something is actually wrong. 🤔

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Ratvan
3 minutes ago, billygoat said:

Crazy! Based on what I have read, there seem to be a few key takeaways regarding the formation of hydrogen sulfide in the sandbed:

  • It's important to ensure that no organics are buried in the sand, especially not under the rock. Decaying organic material on the underside of uncured live rock is a common catalyst for the generation of hydrogen sulfide.
  • Fine sandbeds appear to be more prone to the formation of sulfide deposits than coarser ones, probably because there is less water movement through the sand. Deep layers of fine-grained substrate such as oolitic sand are at the highest risk.
  • Water movement through and over the sandbed seems to be the single most important factor at play in preventing the formation of sulfide deposits. The author of this excellent article on hydrogen sulfide in home aquaria reports that he operated a reef tank for ten years with no issues (1-2 inches fine oolite as substrate), then decided to break his system down to upgrade. When he did this he removed his sand and placed it in a bucket in his garage. There was no smell and no evidence of metallic deposits upon removal, but after sitting in a bucket with no circulation for two weeks the sand was grey in color and reeked strongly of sulfur. This seems to suggest that proper circulation is critical to ensure the long-term health of the sand.
  • Benthic microfauna likely play an important role in maintaining the health of a deep sandbed, as their burrowing activities create passageways for water to move throughout the sand, ensuring that the microbes that live there are supplied with oxygen. Anoxia is a precondition for the formation of hydrogen sulfide.

This information leads me to wonder quite a bit about what is going on in my own sand, as it has sat almost undisturbed for nearly eight months now. There's a chance that the microbes down there are up to no good, but my instinct is to simply leave things alone. The tank looks good as it is, so perhaps it is best not to go poking around too much until I have a reason to suspect that something is actually wrong. 🤔

That is more or less the same things that I came out with, I had some Egg Crate under my rockwork that was covered in sand. I think that this would be where the majority of the issue arose. Also I used possibly the tiniest grain of builders sand ever lol. 

 

However, I have been trying to replicate the effect (because I'm interested and I find it funny watching people evacuate the office) so far I am at 2 weeks and not getting much on my Gas Detector. Terrible photo incoming from under my desk 😄

 

20190813_152415.jpg

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billygoat
36 minutes ago, Ratvan said:

However, I have been trying to replicate the effect

Oh man... you kept the sand so you could do it again!? You are one of a kind, @Ratvan😂

 

You may need to add some sort of organic nutrients to the water in order to get sulfide deposits to form. Bacteria in the sandbed produce hydrogen sulfide because they are turning to sulfate (which is abundant in seawater) as a catalyst for the oxidation reactions that drive their metabolism, but they of course need something to "eat" in order to be doing this in the first place. Maybe since you used builder's sand there are less organics down there? It's hard to say for sure.

 

Man... you kept the sand so you could do it again. I can't get over it. 😂😂

 

EDIT: Also how old was your pico when you started to have problems with the sandbed?

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Nano sapiens
40 minutes ago, billygoat said:

Crazy! Based on what I have read, there seem to be a few key takeaways regarding the formation of hydrogen sulfide in the sandbed:

  • It's important to ensure that no organics are buried in the sand, especially not under the rock. Decaying organic material on the underside of uncured live rock is a common catalyst for the generation of hydrogen sulfide.
  • Fine sandbeds appear to be more prone to the formation of sulfide deposits than coarser ones, probably because there is less water movement through the sand. Deep layers of fine-grained substrate such as oolitic sand are at the highest risk.
  • Water movement through and over the sandbed seems to be the single most important factor at play in preventing the formation of sulfide deposits. The author of this excellent article on hydrogen sulfide in home aquaria reports that he operated a reef tank for ten years with no issues (1-2 inches fine oolite as substrate), then decided to break his system down to upgrade. When he did this he removed his sand and placed it in a bucket in his garage. There was no smell and no evidence of metallic deposits upon removal, but after sitting in a bucket with no circulation for two weeks the sand was grey in color and reeked strongly of sulfur. This seems to suggest that proper circulation is critical to ensure the long-term health of the sand.
  • Benthic microfauna likely play an important role in maintaining the health of a deep sandbed, as their burrowing activities create passageways for water to move throughout the sand, ensuring that the microbes that live there are supplied with oxygen. Anoxia is a precondition for the formation of hydrogen sulfide.

This information leads me to wonder quite a bit about what is going on in my own sand, as it has sat almost undisturbed for nearly eight months now. There's a chance that the microbes down there are up to no good, but my instinct is to simply leave things alone. The tank looks good as it is, so perhaps it is best not to go poking around too much until I have a reason to suspect that something is actually wrong. 🤔

Important topic!  Numerous threads from the last decade or two show that not stirring the sand bed on a Pico and small Nano tanks (at least once in a while) typically does not provide a good outcome if one wants to keep the tank running in optimal condition for longer period (years).  Time wise, typically somewhere between 8 months and about 1-1/2 years on a small nano before negative effects are seen and then the distinct possibility of a crash.  I ran into this issue early on at around the 1-1/4 year mark with my 12g nano when I lost many of my corals and have been regularly maintaining my sand bed since then for 11 years now.

 

How much to clean?  That's a good question as each system is unique in it's assemblage of animals, filtration, etc. and the amount of detritus it produces.  Vacuuming detritus from a small section every month or so would be a good place to start, IMO.  As mentioned, using a turkey baster to blow out an area that can't be reached with a vac is helpful.

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Ratvan
2 minutes ago, billygoat said:

Oh man... you kept the sand so you could do it again!? You are one of a kind, @Ratvan😂

 

You may need to add some sort of organic nutrients to the water in order to get sulfide deposits to form. Bacteria in the sandbed produce hydrogen sulfide because they are turning to sulfate (which is abundant in seawater) as a catalyst for the oxidation reactions that drive their metabolism, but they of course need something to "eat" in order to be doing this in the first place. Maybe since you used builder's sand there are less organics down there? It's hard to say for sure.

 

Man... you kept the sand so you could do it again. I can't get over it. 😂😂

 

EDIT: Also how old was your pico when you started to have problems with the sandbed?

Well technically I can get away with it as I build roads and sewers. So I can argue that I am investigating the effects of saltwater on anaerobic bacteria within the waste water system. Yeah I throw nothing out. Ever lol, Also fairly sure I stole the sand from the bins out back. Once I'd taken all the general construction waste out and rinsed a few dozen times

 

I "feed" the tank a couple of times a week once I have finished target feeding with reef roids. I mix it in a plastic cup so i rinse the cup out and dump it in. 

 

The Pico was not old at all, 2 Months? 3 Months? 

 

I might send some of this off to the people who I use to do my Soil and Water Investigation reports to see exactly what sort of organics that I found

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