Bubbles in Sandbed?

[jburke30]

Greetings All,

 

I've had a number of problems with high nitrates for a couple of months now (reqular water changes have little effect on the buildup, and I can't seem to locate the real issue). So, I decided to try to balance the high nitrate buildup with increased aglae growth. To do so I bought 2 55w PC lights for my 20 gallon from AHSupply.com (which by the way went flawless), and set those up over the tank. Well it's been about 3 - 4 weeks now, and the algae growth has improved dramatically. However, it looks like I'm getting some brown diatom growth in the sandbed, and now in areas of heavy growth there are a bunch of air bubbles.

 

I'm really curious about these bubbles, and a couple of possibilities have come to mind. I first thought that maybe my Blue Damsel was building a bubble nest of some type (though I can't seem to find any evidence in the tank or in my research to support this). After that I had the horrible thought that maybe the tank was leaking slowly on the bottom, but a quick check proved that wrong. Then yesterday it hit me that maybe this was the algae converting nitrate into a gas. Any experienced reefers out there seen anything like this?

 

Jason

[Fishiebusiness]

Bubbles on algae and plants are usually oxygen and the process is called pearling. Its the end result of photosynthesis, the conversion of CO2 into sugars and oxygen by plants. Nitrates are not converted to gaseous nitrogen by plants, but rather incorporated into their tissue. Those bubbles are oxygen, which is good for fish and other animals. Just watch the pH, as a lot of oxygen being released means a lot of CO2 being fixed, which can lead to pH swings.

[jburke30]

Originally posted by Fishiebusiness

Bubbles on algae and plants are usually oxygen and the process is called pearling. Its the end result of photosynthesis, the conversion of CO2 into sugars and oxygen by plants. Nitrates are not converted to gaseous nitrogen by plants, but rather incorporated into their tissue. Those bubbles are oxygen, which is good for fish and other animals. Just watch the pH, as a lot of oxygen being released means a lot of CO2 being fixed, which can lead to pH swings.

 

Cool. Thanks for the reply. This is the first time I've seen this, so I was clueless .

 

The pH in the tank has been stubbornly stable at 7.7 (Kh 11) for the past couple of months (which is below the recommended value). I've tried to use a chemical pH buffer, but it only stays at the new level (usually 8.0 - 8.2) for a couple of hours before it goes back down to 7.7. I've stopped trying to buffer since it seems like a constant up and down is worse than a stable lower value (btw the pH of my source RO water is 8.3, but something in the tank is keeping it at 7.7).

 

Will the extra oxygen help raise the pH? Or is there some reason to worry about it dropping more?

 

Thanks again.

 

Jason

[Fishiebusiness]

If i remember correctly, the pH will go up once co2 is taken out of the water. So, having lots of photosynthesis should raise your pH somewhat.

[tinyreef]

jburke30,

 

that's really low pH! 7.7? what kind of sand do you have in the tank? and what type of plants? what time are you taking your pH readings versus your set photoperiod? although the plants produce o2 during the day at night the co2 is killing your pH. after the photosynthesis comes the respiration for the plants which produces the co2 which becomes carbonic acid hence a depressed pH.

 

fishiebusiness is correct about the respiration of the plants but you could also be right if it's the diatoms or dinoflagellates that covers the substrate like a mat. when i first setup my refugium, it went into overdrive on both issues and i had a carpet with bubbles of nitrogen underneath.

 

imo your main concern should be the pH level.

 

(edit) jburke30, i just realized i ASSuMEd you are raising a reef which a low pH is not conducive to. if you're just looking for a macroalgae tank with fish then nevermind the above.

[tyoberg]

Either your pH kit is broke or you've got a huge surplus of CO2. Aeration may be part of the problem. The quality of air in the room is probably also a contributor--open a window!

 

Here's an article on indoor air quality (specifically CO2) on pH.

http://www.advancedaquarist.com/issues/apr...r2002/short.htm

 

Does your algae have a dusty appearance and is easily vacuumed up (diatoms) or does it look like snot with bubbles in it (dinoflaggelates)?

 

Ty

[jburke30]

Originally posted by tinyreef

jburke30,

 

that's really low pH! 7.7?  what kind of sand do you have in the tank? and what type of plants?  what time are you taking your pH readings versus your set photoperiod?  although the plants produce o2 during the day at night the co2 is killing your pH.  after the photosynthesis comes the respiration for the plants which produces the co2 which becomes carbonic acid hence a depressed pH.

 

fishiebusiness is correct about the respiration of the plants but you could also be right if it's the diatoms or dinoflagellates that covers the substrate like a mat.  when i first setup my refugium, it went into overdrive on both issues and i had a carpet with bubbles of nitrogen underneath.  

 

imo your main concern should be the pH level.  

 

(edit) jburke30, i just realized i ASSuMEd you are raising a reef which a low pH is not conducive to.  if you're just looking for a macroalgae tank with fish then nevermind the above.

 

Well, let's see. I usually take the pH reading in the evening after about 8 hours into the photoperiod. The pH has been very frustrating for me, and has been a constant problem. However, I've tried a number of different suggestions (from research I've done), but nothing seems to help (I've aimed the powerheads at the water surface, I've added more powerheads to increase circulation, I added an air pump to the powerheads).

 

When I first brought this problem up everyone thought that it was decaying mater in the sandbed that was causing the problem (which made sense to me since there had been a time when I was overfeeding to sustain a Mandarinfish before she was moved to a better home). Also, poor lighting (which is now fixed) and too many hermit crabs reduced my tank's plant life to nothing.

 

Obviously my biological cycle in completely out of balance, and my hope was that the new lights would cause more algae growth, which would in turn reduce nitrates and add more oxygen to the tank. But something is going wrong since I'm getting a very fishy smell from the HOB filter and the prefilter sponge on the powerhead. The next step I was planning on taking was to buy some macroalgae and add it to the tank to really kick start the nitrate reduction process (though my hope was that the tank would start to balance itself out without this).

 

Another point is that I recently (6 weeks ago) moved everything into a new 20 gallon long tank (which I really like), and at that time I completely rinsed the sandbed. I thought that would fix my decaying matter problem, but my nitrates still seem to climb a bit too quickly (possible decay from the live rock?).

 

Also, I just finished cycling the refugum tank (tests last night show that amonia and nitrite are both at 0). Thought these tanks are not connected yet, and the lighting in the refuguim is still too low (I'm going to put in a 32 watt PC kit, but right now it's only at 15 watts on 10 gallons).

 

At this point I'm just trying to be paitent, and not do anything drastic to the tank. I welcome any ideas on fixing the CO2 issue, and dealing with the pH.

 

Main Tank specs:

20 gallon long

110 watts PC

125 Penguin Bio-Wheel (I just took the wheel out, and replaced the carbon yesterday)

114 Zoo Med Powersweep (the sweeping finally died, and I don't think this is enough circulation right now, but I don't know what to add or how much)

Standard heater (170 watts I think - I keep the tank at 80 degrees)

10 lbs of live rock (I want to add more, but the LFS that I use just went out of business, and I haven't found a new one that I like)

20 lbs of substrate (crushed shell, seashell and beach stone mix, argonite mix - all mixed together. It looks really nice IMO

 

Refuguim Tank specs:

10 gallon

15 watts 50/50 blub

10 lbs of argonite mixture

114 Zoo Med Powersweep (again sweeping is dead)

A really cheep HOB carbon filter (The idea is to put the Penguin in the refuguim when they're connected, and get rid of this thing).

 

Main Tank Chemistry:

0 amonia

0 nitrite

100 nitrate

10 KH

7.7 pH

 

Refuguim Tank Chemistry:

0 amonia

0 nitrite

50 nitrate (I added in some water from the main tank to jump start algae growth, perhaps a bad decision)

11 KH

7.7 pH

 

Sorry for the length, but I wanted to present a complete picture. Also, right now the tank is a fish only tank, but I do want to add coral in the future. I'm not going to do that untill the system is stable and water quality is better.

 

Jason

[jburke30]

Originally posted by tyoberg

Either your pH kit is broke or you've got a huge surplus of CO2.  Aeration may be part of the problem.  The quality of air in the room is probably also a contributor--open a window!

 

Here's an article on indoor air quality (specifically CO2) on pH.

http://www.advancedaquarist.com/issues/apr...r2002/short.htm

 

Does your algae have a dusty appearance and is easily vacuumed up (diatoms) or does it look like snot with bubbles in it (dinoflaggelates)?

 

Ty

 

The air is on in the house, so opening a window would be problematic (especially with the killer heat we've been getting in St. Louis recently)

 

What would you recommend for alternate airation methods (I have an air pump, but how much should be pumped into the tank, and is it better to get a diffuser or to hook it to the powerheads?)

 

As far as algae, I have both, but the stuff in the sandbed is the snotty kind (I have diatoms on the tank glass and live rock).

 

Jason

[tinyreef]

there's definitely something wierd going on in your tank. i'd wait a bit as the refugium settles in.

 

i'm surprised at the high dkh with that pH. they should be battling it out. but your refugium is showing a slightly higher dkh than your main tank. this could be the aragonite dissolving and buffering the refugium which will slowly seep into the tank at whatever rate you have set. at that pH your aragonite and rock should dissolve at a very quick pace.

 

i'd let it sit a bit and wait. the next step i would suggest would be a aragonite sand addition to your main tank or more depth in your refugium. the cc may not be dissolving as fast (releasing buffer) due to its larger size, much like saturation conditions in kalk additions.