Unsolvable chronic low pH

[MikeTR]

Ok so my power of Hydrogen is not so powerful. 14gal nano cube, just modified the back to use a canister filter, using center chamber as a fuge growing chaeto (not running reverse light cycle). I think this has gone a long way at keeping my nitrates at undetectable levels. Weekly water changes of 2 gals. Sometimes 3-4 gallons if the pH tests at 7.6.

 

My pH is usually 7.7 in the morning.. sometimes 7.6. Evening it is 7.85 if I'm lucky. If someone can solve this problem I swear I will buy you something. =). So here's my parameters. 0 ammonia, 0 nitrites, 0 nitrates, 0 phosphates, dKH 12-14 (tired of adding buffer, not working!) Ca 400-450. Temp 80.1. 2 different LFS said Mg levels are fine. So I've acquired my nano from a friend who had it set up for about a year. A couple months before he gave it to me, he said he changed the sand. So i've done practically everything I can think of to get the stupid pH up but nothing helps. Last night I just recently took out a lot of the live rock and did a 3 gallon water change.. I was trying to see if the rock was too old and causing excess CO2 from nitrification. pH of the mix water was 8.2.. pH of the tank water was 7.6.. after the water change the tank water raised to 7.9.. only to be 7.7 this morning. Bummer. A few weeks ago I did a 5 Gal water change (stirred up all the sand) before sucking out the water and ended up with basically the same results. Whats the deal here. I have a tomato clown and a royal gramma. (they get along fine now after one brutal fight) was kinda fun to watch. lol. So I don't think the bioload is too great..I have a bunch of coral and an anemone and who knows how they are surviving. HELP!!!! All of it looks OK.. but I fear it's all gonna die. Oh and I have done the aeration test and the pH did not rise.

[Mr. Fosi]

... dKH 12-14 (tired of adding buffer, not working!)

 

Good, cause that is too high. 8-11 is a better range to shoot for.

 

Have you tried aerating the water either with a diffuser or a skimmer? Have you opened the window of the room the tank is in?

 

It sounds as though the air of the room your tank is in is enriched in CO2. In that case, you will need to aerate with air from outside that is not CO2-enriched.

[MikeTR]

My tank is in the living room by the front door of my condo.. so it gets a rush of fresh air daily. I guess I really need to turn all the pumps off and aerate a gallon of tank water outside. Will do that tonight and post results. I'm gonna really be ticked off if that is the problem.. Guess it's my own fault for not trying it earlier.. and I guess I'll have to air out the house more.. really sucks cuz i live in FL and it's hot!

 

I do have a Hanna digital PH meter so I know the readings are right. You can get them all day long on ebay for 25$ and it is accurate. You do have to buy the calibration solution as you'll have to calibrate it weekly. Guess that's the only downfall I've seen..but the solution is like 3-4$.. cheaper than test kits. Anyone else have ideas on what my problem is?

 

Good, cause that is too high. 8-11 is a better range to shoot for.

 

Have you tried aerating the water either with a diffuser or a skimmer? Have you opened the window of the room the tank is in?

 

It sounds as though the air of the room your tank is in is enriched in CO2. In that case, you will need to aerate with air from outside that is not CO2-enriched.

[Mr. Fosi]

Well, it gave you a believable reading from your freshly mixed SW so it probably isn't much off (if it is off) for the tank.

 

You could just run an airhose in from outside to your tank... It isn't an elegant solution but it might for you.

 

When you do your outside test this evening, let it run for at least an hour before you check it again. You are more likely to get an equilibrium reading if you wait several hours (depending on the volume of water you aerate).

[lakshwadeep]

Try checking here for some help:

http://reefkeeping.com/issues/2004-09/rhf/index.php

[zemuss]

Wouldn't a simple air pump with a air stone help raise the PH level and stabilize it?

 

"Z"

[davidncbrown]

I have a bunch of coral and an anemone and who knows how they are surviving.

 

Are you sure its not just your tester/test kit? Try a different one. Test something of a known pH. I mean if everything IS fine.... maybe its just your tester.

[Mr. Fosi]

Q

Wouldn't a simple air pump with a air stone help raise the PH level and stabilize it?

 

A

It sounds as though the air of the room your tank is in is enriched in CO2. In that case, you will need to aerate with air from outside that is not CO2-enriched.

 

Q

Are you sure its not just your tester/test kit? Try a different one. Test something of a known pH. I mean if everything IS fine.... maybe its just your tester.

 

A

Well, it gave you a believable reading from your freshly mixed SW so it probably isn't much off (if it is off) for the tank.

[vangvace]

It sounds as though the air of the room your tank is in is enriched in CO2. In that case, you will need to aerate with air from outside that is not CO2-enriched.

 

Too piggyback off of this...

 

How much surface movement do you have in your tank?

Still running it as a closed lid?

[thecowkid]

Might help. But in my aquapod I have to pop the lid open for a few hours every few days or the ph will slowly creep down. So I am going to cut a little 1/2" hole and add a micro fan to solve the problem. The air in the hood will get really stale even though the rooms air is refreshed constantly.

[davidncbrown]

Ah good point fosi. I was getting ready for work so I guess I didn't read the post very carefully. If it IS a CO2 problem, kalkwasser drip could help bind up some of that excess CO2 and possibly bring the pH up, but watch your KH. Its curious to me that you have macro growing, yet you are still having the excess CO2 problem though...

[Mr. Fosi]

Its curious to me that you have macro growing, yet you are still having the excess CO2 problem though...

 

Not enough macro or not enough light for long enough can add up to a lack of impact.

 

So, OP, any word?

[davidncbrown]

very true. I dunno it just seems like all of this should be helping if CO2 is the issue. I run the light on my macro for about 16hrs a day, thats what works on my tank. Maybe if the OP bumped up his lighting schedule for the chaeto...?

[Mr. Fosi]

Perhaps. *shrugs*

 

I'm hoping he comes back and gives us an update. Some additional info about his amount of macro and lighting would be a plus as well.

[lakshwadeep]

A reverse cycle on the chaeto would help to balance out pH drops at night.

[Mr. Fosi]

Right, but the OPs problem isn't just a night-time thing... It's low all the time.

 

This is one reason why I am hypothesizing that it is a macro/light amount that's keeping it from being a more effective solution.

[davidncbrown]

For freshwater planted tanks that have CO2 injection you can get CO2 test kits for relatively cheap. I wonder if these actually work, and if they would work for a salt water tank. If the problem of low pH persists maybe high CO2 concentration could be ruled out with one of these.. There *could* be some other issue I guess.

[MikeTR]

Wasn't able to do the aeration test outside last night.. but I promise I will tonight as soon as I get home and post the results. I have removed the front lid altogether as I was having heat issues. The return is pointed as far to the surface as i can get it so it's got a nice ripple on the surface. I normally run the lights on a 12 hour cycle.. except for the last week or so it's been about 8hrs to try and kill off some brown algae. Been battling this low pH for almost as long as I've had this.. (since Jan) pH this morning was 7.8..I did add some buffer last night.. curious to see what it is when i get home in about an hour but I'll guarantee it to be 7.9. I have a good hand-sized ball of chaeto in the center chamber.. not running any additional lights for it. I moved the daylight bulb to the back, and removed the drip tray that was covered in coraline..so I'm pretty sure the chaeto is getting enough light. It's a little noiser, but eh I don't care .. I also recently added some limestone base rock which is supposed to dissolve bicarbonate into the water that I got from the LFS. It's just a small chunk.. was thinking about adding more.. but it's BRIGHT white . Definitely base rock. About a week ago my brother gave me something he called ribbon grass and that's growing in the back corner. It looks like blades of grass that grow in a line. I think the aeration test will hold the truth if it's a CO2 problem. I'll be aerating with a wooden airstone so lots of bubbles. Results should be posted within 3 hrs.

 

For freshwater planted tanks that have CO2 injection you can get CO2 test kits for relatively cheap. I wonder if these actually work, and if they would work for a salt water tank. If the problem of low pH persists maybe high CO2 concentration could be ruled out with one of these.. There *could* be some other issue I guess.

 

 

OH i should add.. you don't know how thankful I am for all of your help!

[Mr. Fosi]

I also recently added some limestone base rock which is supposed to dissolve bicarbonate into the water that I got from the LFS.

 

CaCO3, biogenic or not, does not dissolve in SW until pH is down in the 6.2-6.5 range.

[MikeTR]

Well fooey... good thing I only paid $2.50 for it.

 

CaCO3, biogenic or not, does not dissolve in SW until pH is down in the 6.2-6.5 range.

[MikeTR]

Mr. Fosi is correct! Excess CO2. Aeration test outside with a cup of water.. PH went from 7.95 to 8.2. Let me tell ya i almost couldn't believe my eyes... so hmm... now I gotta figure out how to deal with this issue in the house. Will try aerating the tank water with the same airstone to start. Guess I can put all my rock back in. I'll take some pics when I get it all put back together.. wow! SOOOOO glad to figure this out.

[lakshwadeep]

Check my link I posted above; there are some tips on using kalkwasser (limewater) or a carbonate solution to help deal with the high carbon dioxide levels and help alkalinity in the process.

[ajmckay]

Hmmm.... Mike, I'm glad that you found your problem. Normally I don't think I would be overly concerned with a pH in the 7.8-7.9 range, as long as it was stable. It's the changing from 8.2 to 7.8 in a short time frame which will kill your animals....

 

Fosi, would the amount of CO2 really cause such drastic changes in so little time? I'm just thinking of stability here... Honestly I don't really know all that much about chemistry & such (only reason I passed the only chem class I ever took was that my lab partner solved everything - was a Harvard guy...), but I think Mike should focus on a plan to keep the pH stable over the long term (not to say that an outside air source wouldn't, I'm just throwing the idea out there).

[Mr. Fosi]

Glad you've found the answer. So many questions never get fully answered.

 

Lak is right, kalk can be used to offset high CO2 (not like adding buffer) but I would suggest avoiding chemical solutions if possible. It's easy to screw up with kalk.

 

I recall someone asking if this is still a closed-top system... Is it? If so, adding a small fan to the hood to refresh the air above the water would help, unless you're pretty sure this is a room-air problem. I don't recall if you already tried aerating with room air?

 

Fosi, would the amount of CO2 really cause such drastic changes in so little time?

 

What do you mean by "so little time"? CO2 and O2 concentrations can change very fast when there are a lot of photosynthetic organisms present and the lights turn on or off.

 

... I think Mike should focus on a plan to keep the pH stable over the long term (not to say that an outside air source wouldn't, I'm just throwing the idea out there).

 

Stability is good but I really wouldn't want to have my tank moving between pH 7.8-7.9 only.

 

Higher pH can help calcification and if you'll allow me a little conjecture, I bet that pH's of 8-8.2 also increase net primary productivity in the tank as stress of low pH is alleviated. Of course, as your pH climbs above 8.2, high-pH stress comes into play as well which is why you want a tight range around 8.0.

[MikeTR]

I don't think I have an issue with stability.. it's at least consistently low. I leave the front lid of the cube off all the time (heat issues with it on). I think I need to get a 5 gallon bucket and start aerating my mix water outside. If the weekly water change with the aerated water doesn't work.. then I may go to changing less water more often and see if that helps. I'd really like to go on vacation at some point if you know what I mean.. so kalk isn't an option.

 

What really sucks is that we have to modify an AIO system. I mean it is a biocube and intended to run with the lid on, with the bioballs in the back, no macroalgae.. a simple carbon filter. Doesn't help that the bastards put a pic on the box of the thing slampacked full of fish, rock, and corals.. like who are they kidding..

 

Hmm.. well if all the above doesn't work then maybe I'll just go back to the basics.. my 10 gal quarantine tank is actually doing better and i'm running just a cheap 10$ walmart filter and a crappy air pump.

 

 

Glad you've found the answer. So many questions never get fully answered.

 

Lak is right, kalk can be used to offset high CO2 (not like adding buffer) but I would suggest avoiding chemical solutions if possible. It's easy to screw up with kalk.

 

I recall someone asking if this is still a closed-top system... Is it? If so, adding a small fan to the hood to refresh the air above the water would help, unless you're pretty sure this is a room-air problem. I don't recall if you already tried aerating with room air?

 

 

 

What do you mean by "so little time"? CO2 and O2 concentrations can change very fast when there are a lot of photosynthetic organisms present and the lights turn on or off.

 

 

 

Stability is good but I really wouldn't want to have my tank moving between pH 7.8-7.9 only.

 

Higher pH can help calcification and if you'll allow me a little conjecture, I bet that pH's of 8-8.2 also increase net primary productivity in the tank as stress of low pH is alleviated. Of course, as your pH climbs above 8.2, high-pH stress comes into play as well which is why you want a tight range around 8.0.