Alkalinity Suck - Chemistry Question

[benstatic]

Hi Guys,

 

On my new 20 gal tank, I notice a large Alkalinity suck from my water. 

My salt (Instant Ocean) - naturally has ~10 or so dKH

On Sunday (2 days ago) - I was at 7 dKH,  I did a water change and got up to 7.5 dKH.

I tested this this morning, I was about 6.5 dKH.

I am guessing this means I lose between 0.5 - 1 dKH per day in Alkalinity.

 

I assume this Alk suck is because my tank is about 3 weeks old, and is growing bacteria like mad, and the by-product is consuming Alk.

I have a single LPS, and its brand new, not even open.  I don't want to further stress him with low Alk, swinging pH, or low Ca.

 

Its going to get tedious to try and correct via water changes, so I am thinking about dosing my tank to keep carbonate levels higher (closer to 8.)

If this is just a bacteria demand (no / very low Ca demand) - can I just dose a Carbonate supplement?

Or do I do a 2 part to maintain Ca levels?

 

If you recommend a Ca supplement in addition - I have a CaSO4 dry supplement for my freshwater setup...  Thoughts on using to dose as part2?  (Part 1 is Seachem Carbonate).

[NanoRox]

Is your pH stable?  Curious what you are using to test the Alk.?  Seems odd that is happening in a 3 wk old set-up 

[benstatic]

pH is stable - but haven't really been monitoring as closely. 

~8.2 or so.  I don't anticipate a pH crash until it hits maybe 5, but if I don't start treating, worried about it.

 

Testing Alk using the API dKH test.

I've read that reproducing nitrifying bacteria make amino acids - consuming available Alk.

 

Just some hypothesizing, I maintain my CO2 injected FW 55gal in the same room, its an enclosed place (basement) and very little circulation in the cold winter months - it could be my water is sucking up CO2?  But - the injection in that tank is only during daylight hours, and the rate is low (it goes through a CO2 reactor, so its quite efficient in diffusion) there is also O2 production by those plants in that tank.

[OPtasia]

The biggest ingredient in alkalinity buffers is usually baking soda (sodium bicarbonate). Any acidic biological function could potentially burn through Calcium or Bicarbonate or both. To me it sounds normal and nothing regular maintenance won't address (water changes, kalkwasser dosing in your topoff water or two part dosing). Remember, pH swings throughout the day are normal and you'll only need to really worry about that if the swings are massive or a sustained drop in pH. 

 

If it were me, i'd do a water change or consider beginning your 2 part or kalkwasser dosing regimen. Corals need a higher pH so that they can utilize the calcium in the water for growth. Remember, 2 part is actually 3 part (Calcium, Alkalinity AND magnesium) so make sure if you make your own home made 2 part not to forget the magnesium component.

 

You might also find this link useful.

[NanoRox]

I'de love to hear what others think.  I'm just getting back into the hobby so its been awhile for me BUT I have not seen Alk decrease so rapidly in a new aquarium personally.  Does not mean it does not happen but that is why I am wondering about the test kit.  I hate to blame kits BUT I have also heard some bad feedback on API test also.  

 

maybe there is  not a problem though. for example...My nano is on its fifth week.  I have several LPS corals a monti cap, several zoanthids, a hammer and frogspawn with lots of live rock and my alk is sitting at 8.1 (using a hanna checker).  My refill water is Fritz and sits around 9,5 dkh.  ph is 8.1 or so.  our parameters are not that far off so perhaps the best thing to do is just watch it for while.   I will say that I dose kalkwasser in my ATO and that has kept everything rock solid and highly recommend it if not now trying it later. 

[OPtasia]

Test reagents do have a shelf life, so the fresher the testing reagents the better. Provided the kits are fresh, most droplet kits are accurate. Sometimes they're a little hard to interpret between the different colors but they're usually accurate. Meter/Probe based kits are also good but you really should have ones you can calibrate. If I remember right, you can calibrate the hanna testers as well as the long probe based meters. What people don't realize is that the probes will occasionally rust or likewise degrade over time and will need replacing eventually. 

 

Six to one and pick em. 

[NanoRox]

2 minutes ago, OPtasia said:

Test reagents do have a shelf life, so the fresher the testing reagents the better. Provided the kits are fresh, most droplet kits are accurate. Sometimes they're a little hard to interpret between the different colors but they're usually accurate. Meter/Probe based kits are also good but you really should have ones you can calibrate. If I remember right, you can calibrate the hanna testers as well as the long probe based meters. What people don't realize is that the probes will occasionally rust or likewise degrade over time and will need replacing eventually. 

 

Six to one and pick em. 

after using the chemical drop tests and now my hanna checker...I'm in love with the thing.  I wish they  (hanna) made one for Nitrates.  

[OPtasia]

1 minute ago, Duane Clark said:

after using the chemical drop tests and now my hanna checker...I'm in love with the thing.  I wish they  (hanna) made one for Nitrates.  

Yeah, they're pretty rad. I use a lot of probe based meters for titration testing in my line of work so i'm dealing with them constantly. Hanna builds good products.

[weston.bechtold]

Personally I would only dose the carbonate, the calcium levels should be fine if there aren't many demanding factors.  Overdosing CA would be detrimental if you plan to introduce more corals soon.

[benstatic]

The API kit seems pretty reliable (at least it acts as I expect it to).  Its also fresh.

You sometimes get a green 'in-between' color which you just have to assume green (between blue and yellow) is a 0.5 reading and just be OK with that level of precision.

 

I haven't felt a need for more expensive test kits yet.  If I were going to start doing A / B testing of conditions / parameters, then I might feel an urge to be more scientific, but this suffices for now. 

 

Dosing Kalk is not something I've looked into - but might be curing a similar condition in your tank without you noticing it exists?

Any thoughts on using CaSO4 (calcium sulfate) as an alternative to CaCl2?  I only ask as I have it on hand.

I can look at adding Epsom salts as Part3.

Quote

Personally I would only dose the carbonate, the calcium levels should be fine if there aren't many demanding factors.  Overdosing CA would be detrimental if you plan to introduce more corals soon.

I am still considering this.  I'll be monitoring my Ca levels to see if any precipitates out of my water column.  That right there might make my decision for me.

 

[weston.bechtold]

4 minutes ago, benstatic said:

The API kit seems pretty reliable (at least it acts as I expect it to).  Its also fresh.

You sometimes get a green 'in-between' color which you just have to assume green (between blue and yellow) is a 0.5 reading and just be OK with that level of precision.

 

I haven't felt a need for more expensive test kits yet.  If I were going to start doing A / B testing of conditions / parameters, then I might feel an urge to be more scientific, but this suffices for now. 

 

Dosing Kalk is not something I've looked into - but might be curing a similar condition in your tank without you noticing it exists?

Any thoughts on using CaSO4 (calcium sulfate) as an alternative to CaCl2?  I only ask as I have it on hand.

I can look at adding Epsom salts as Part3.

The api test kit or any color matching test kit leaves room for error, but hanna tests are expensive, a good medium is the red sea pro where you are looking for a drastic change in color, as long as you take it slow they are very accurate.

 

[NanoRox]

7 minutes ago, benstatic said:

Dosing Kalk is not something I've looked into - but might be curing a similar condition in your tank without you noticing it exists?

very possible.  My alk dropped to 7.5  and my ph to 8.0 so I got it back up with sodium bicarbonate and now maintain with kalk.  yours just dropped so quickly overnight.  Mind you I don't think any of the numbers we have been throwing around are bad necessarily but for me I would like my alk around 8.5 or 9 and my ph at 8.3.  My Calcium is solid at 460 so not worried about that.   honestly, all things considered, I would go to bulkreefsupply.com,  use their alk calculator and get the alk where you want it (within reason...not too fast) and then let it settle for a bit and see what it does.   my 2 cents.  :-) 

[OPtasia]

29 minutes ago, weston.bechtold said:

Personally I would only dose the carbonate, the calcium levels should be fine if there aren't many demanding factors.  Overdosing CA would be detrimental if you plan to introduce more corals soon.

Yeah only dose what you can test for and monitor. I think what we're looking at is just a slight imbalance of cal to alk. If you test for calcium and it seems to be at an acceptable level and the pH is remaining lower than you'd like, then you're looking at a bicarbonate or very rarely a magnesium imbalance. Water changes and/or dosing with 2 part will fix the OP's issue. That, plus realizing pH swings throughout the day are normal end to biological functions.

[benstatic]

Allright,

Well, knowing this was an issue, I already dosed Alk this morning (after my 6.5 measure) to get it up.  I should have taken a reading immediately after, but needed to get to work.

I added 10mL Seachem Carbonate, which according to the dosing instructions, should have raised me put me at about 7.9 today (+0.5 meq).

 

I am going to not add any Calcium additive for now - I just don't think there is any Ca demand in my tank, unless my 1 astrea snail is going bonkers.

Some amount of Alk will be consumed by my tank today.  I will measure tomorrow (same time I measured when I got my 6.5 reading) and see where I am at.

 

If I read below 7 tomorrow, I will add another 10mL dose until I get a reading I like (as close to 8 as I can measure). 

If I read 7.5 then a 5mL dose

If I read 8 or greater - then no dose 

 

I'll measure Ca, Alk, pH during the next few days as I do this - and you guys can see what you think.

There will prob be a water change in there at some point too (usually do one on Wed eve).

Thanks,

[niQo]

I had something similar happen when I set up my tank (50 gallons). It only had a few (neglected) corals and used up about 1 dKh every week, but calcium remained somewhat high. However, after a few months I had to dose less and less. Currently I do not dose anything yet my Alkalinity remains stable. Keep an eye on it, because it may change and your Alkalinity may rise too high. 

[reefroid]

I used api alk test kit was reading 6 dkh. I switched to red sea pro kit and got way different results at 9dkh. don't go cheap on test kits invest in a good kit like red sea!

[Clown79]

I would test your newly made saltwater, then test your tank after a waterchange.

Test every day at the same time for a week.

 

This will help you determine what's being consumed.

I would test ca and alk. They work together and as you raise one, the other drops.

 

2 part dosers are great as they keep the 2 in balance.

 

 

[HM3105]

Personally, when the results of my test do not come out where they should be I run the test again using a different brand. I've known several people who ran tests and kept getting low results then discovered the test kit was reading bad. 

[MuffinMonster]

I was having the same issue- its due to the new tank, it will slow down after a while after your ecosystem becomes more established. Are you running a skimmer on your tank? my low alk I believe was causing my pH to be low. My pH is currently sitting at 7.5-7.8 and my Alk is sitting at 7.5dKH, iv been trying to raise alk slowly the past couple weeks. Just by water changes though, not dosing anything. I still would like my pH to be higher, but I'm not about to start chasing it and get a headache from not being able to achieve a higher number. So right now I'm just focusing on a couple water changes a week trying to get ALK up.

[OPtasia]

1 hour ago, Dakoda said:

I was having the same issue- its due to the new tank, it will slow down after a while after your ecosystem becomes more established. Are you running a skimmer on your tank? my low alk I believe was causing my pH to be low. My pH is currently sitting at 7.5-7.8 and my Alk is sitting at 7.5dKH, iv been trying to raise alk slowly the past couple weeks. Just by water changes though, not dosing anything. I still would like my pH to be higher, but I'm not about to start chasing it and get a headache from not being able to achieve a higher number. So right now I'm just focusing on a couple water changes a week trying to get ALK up.

That's not bad advice at all. It's all about finding the balance between your bio load and alkalinity. Water changes are a great way to get there without having to dose as much, or doing water changes exclusively (smaller amounts, more often). I'd still test for calcium and alkalinity and it's a good idea to log it on a chart (including water changes) so you can see what it is specifically your tank needs. If you have more corals and inverts that are burning up more calcium and alkalinity buffers faster than you can water change, then supplementing with 2 part dosing or kalkwasser also helps a lot. 

[benstatic]

water changes will be half how I deal with this.

 

Why all the hate on API test kits?  They work perfectly fine.  Sure, its hard to tell the difference between 10 and 20 ppm Nitrate...  I haven't found that matter to my tank, its a range, and I don't expect to get a precise value.  You guys like to burn your money on overprice test kits.  Maybe some day I'll eat my words...

 

I am not concerned about the test kit - it is completely reliable based on the numbers I have been getting.  When I do repeated tests, I get repeated results.

Testing fresh mixed saltwater gives me expected results (about 9-10 dKH via Instant Ocean)

Water changes give me expected results (a 5-10% water change resulted in about a ~0.5 dKH improvement.)

 

I tested my water this morning (same time in the morning as previously)

Remember, this was after a 10ml dose of Seachem Carbonate the previous day (yesterday AM = 6.5, then dose 10mL Carbonate).

This AM, I had an 8 dKH - which is where I want it.  I didn't dose today.  

Calcium is at 340 - 360 or so which is about right in line with the fresh mix IO.

Will test tomorrow AM and get another reading, potentially dose if <= 7.5

 

But I notice I am growing some algae, so its cleaning and water change night tonight.  I will probably do ~10% or so (2-3 gallons).

 

I am stressing my Trumpet coral out with all my monkeying around in this tank.

I installed him Friday, moved him Monday (to higher light), my electric blue crab uses him as his bed, I dose a large Alk swing, another water change tonight. 

He look liked like he was spitting Zooxanthella this morning (big long string of goop coming out of one head this morning).

 

Hopefully I can start letting things just be here soon and get this more routine.  My zoanthids and mushroom look ok.

 

[NanoRox]

16 minutes ago, benstatic said:

Why all the hate on API test kits?  They work perfectly fine.  Sure, its hard to tell the difference between 10 and 20 ppm Nitrate...  I haven't found that matter to my tank, its a range, and I don't expect to get a precise value.  You guys like to burn your money on overprice test kits.  Maybe some day I'll eat my words...

no one is hating on the test kits necessarily.  It was one thing to look at.  If you feel they are accurate (not just consistent) then no issues there.  the more I read through this thread and the suggestions offered I think the best suggestion is to just let things settle down a bit. 

[Clown79]

I wouldn't dose at this point.

 

You need to know what your newly mixed water is and that's what you should be maintaining.

 

Dosing shouldn't be about reaching a certain number. It's about stability.

 

New tanks have instability. New sands can even effect alk.

 

With one coral, messing around with dosing isn't advised. Waterchanges on a weekly basis should be enough.

 

Dosing is normally advised for when you have a lot of sps and or lps and it's to replenish what is consumed.

 

1 coral shouldn't drop alk from 8 to 6.5 in a day. And raising alk from 6.5 to 8 in one dose can become an issue. That's more than a dkh.

 

Your ca is low at 340-360, as you raise your alk, your ca will drop.

 

The best advice: test your new salt water for ca and alk.

 

Reg. Instant ocean should also be mixed for 24hrs prior to use.

[benstatic]

Quote

1 coral shouldn't drop alk from 8 to 6.5 in a day.

I don't look at my coral as the culprit here - but more so the bacteria. 

Its not about dosing to provide for growth or chase a number.  I am trying to avoid a pH crash - and as you say - maintain stability (0.5 drop per day isn't what I would call stable). 

I also don't want to have to water change daily. 

 

My tank is sucking up 0.5 dKH per day, which if I tried to achieve through water changes would means a 2 gallon change per day until things stabilize.

I am fine with 2X water changes per week (for now).  So I have a feeling this means dosing if I don't want Alk to drop below 6.  

 

The +1.5 dKH in one dose was probably a drastic step - I agree.  I am looking to get stability, and not have to do daily water changes. 

My doses in the future will be 2.5 - 5mL in amount.

 

Quote

Your ca is low at 340-360, as you raise your alk, your ca will drop.

I thought this too...  This might explain it better than I will be able to - as most people will not believe a 5 week old reefer at his word: http://www.reefkeeping.com/issues/2004-12/rhf/

See the nitrification section for what is happening in my tank.

 

IO naturally has about 340-360 calcium in their newly mix salt.  I agree its low.  

After my dose, the measurable Ca in my water remained unchanged which falls inline exactly with what reefkeeping magazine has described..

When its time, I am thinking about switching salts (maybe reef crystals or the Seachem salt - not high on my research list). 

For one LPS and a snail - my salt is fine for now.

 

 

[Clown79]

I never test ph. 

 

If your alk is in normal range, your ph should be too as they work together. 

 

There's a reason why ppl don't recommend dosing in a new tank, because it's new. It takes time to balance things out.

 

I have never heard of bacteria effecting alkalinity.

 

C02 effects ph and if ph drops to low levels then alk will start to decline- that's whats happening in the ocean now.