low pH problems

[Serra]

I am having trouble getting my pH up in my 37 gal softie tank. The tank has been up for 6 or 7 months. Here is the set up:

25 lbs live rock
2 gal HOB mech. filter /chaeto scrubber
2 maxijet 600
2 T5 lights
3” sand bed

pH= 7.8
ammon=0
nitrates = 0
KH =11.6
Alk = 4.2
Cal = 430

Livestock = mushrooms and polyps, 1 cleaner shrimp and 1 geometric hawkfish. I do a 5 gal. water change per week. I use buffered DI/RO for top off and changes. Feed a little twice a day.

Any ideas why I can’t keep my pH up?
Thanks…

 

[down and outman]

I've had the same problem. Been dosing with two part formula. Had to increase the alkalinity part with baked soda ash to keep my ph up. Bake baking soda at 400 degrees for an hour to drive off the carbon dioxide. This will help it to increase your ph and alkalinity. I've found both work together. Your alkalinity is low as well. Should be around 9 - 12. There dosing instructions at www.bulkreefsupply.com and a lot of useful info.

 

[Peter Eichler]

<a href=showthread.php?s=&postid=12564260#post12564260 target=_blank>Originally posted</a> by down and outman
I've had the same problem. Been dosing with two part formula. Had to increase the alkalinity part with baked soda ash to keep my ph up. Bake baking soda at 400 degrees for an hour to drive off the carbon dioxide. This will help it to increase your ph and alkalinity. I've found both work together. Your alkalinity is low as well. Should be around 9 - 12. There dosing instructions at www.bulkreefsupply.com and a lot of useful info.

Alkalinity is not low, that's meq/l which translates to 11.76 dKH, though I'm not sure why Serra is listing KH and Alkalinity. At least we know the two test kits are fairly close...

Serra, it's most likely a lack of gas exchange and a buildup of CO2. Take a sample of your water and heavily aerate it outside and then test the PH of that water. If the PH is higher than your tank that's your problem. The lack of a protein skimmer and low flow is probably the culprit.

 

[Serra]

Thanks Peter. I have an Aqua C Remora skimmer on it but forgot to add it to the list. I also tilted the power heads up to create more surface turbulence in order to better facilitate gas exchange but I will test the inside and outside air effect.

 

[down and outman]

My bad! I use kdh scale for alk. ( At work we use mg/l, now we're getting confusing!) I'll check on the gas exchange myself. Been considering running the skimmer airline outside of the cabinet to draw fresher air than what's inside my cabinet. My powerheads are aimed up towards the surface as the Koralia 4's are a bit too strong.

 

[Serra]

For anyone that is interested...the result of the experiment is that after aerating the water outside for a couple of hours, the pH tests at 8.4.

My conclusion is that I need O2 badly. I have opened the whole house and will test all my tanks in the AM. Thanks for that heads up Peter! You're the man.

 

[tufacody]

I thought this was my problem once too, and opened up all the windows and doors, lol. Then I realized I just wasn't letting my new salt mixes aerate long enough for the PH to go up. For me it takes a good 3 days of mixing before the PH climbs up to 8.2.

 

[Peter Eichler]

Happy to hear you figured out the problem. Hopepfully it's not a case of the house being sealed up too tight and having higher CO2 levels. If that's the problem more gas exchange might not help matters much. I've got an older home so I don't have that issue, I just get to pay higher utility bills every month Anyhow, if directing the powerheads towards the top helps with the PH you might want to consider one of the mod kits for one of your MJs or a Koralia to get the surface moving even more.

 

[Serra]

I think it was opening the house because my larger tank's pH went up also and I did nothing to it. I will just have to crack windows more often. Can't wait until it's over 100 outside.

Will check the pH this morning and see what a closed house did to it.