Low pH....Need advice

[Simon1]

My pH has been low 7.9 to 8.0 since I began a month ago. I add buffers(Seachem pH 8.3 and Kent Superbuffer dKH) and the pH will be normal for the rest of the day, but when I test the next day, it will be down again. I test in the AM and after the lights have been on for eight hours. My tank appears to be cycled with Ammonia and Nitrite levels being 0. My Nitrate levels are around 3.0ppm . My CA level is around 300ppm, and Alkalinity is normal (Red Sea alk. test doesnt give a number, only a color that is within normal parameters). I have been using Tropic Marin sea salt mix since day one. All that is in the tank at this time is LR ( with a pH of 7.9, I know nothing could survive). However, I do have a ton of copeapods that popped up a week ago. All of my test kits are by Red Sea except for pH which is by La Motte.

NH3/NH4 = 0
NO2= 0
NO3= 3.5ppm
SG=1.024
Ph = 7.9-8.0
Alk = normal... sorry no #
CA = 300 ppm
PO4 = <.2ppm
What am I doing wrong?

 

[Anonymous]

Hey Simon,
Just a thought... you may want to check and see if you have too much CO2 in your water. Easy to test: Take about a quart of water from your tank, drop in an airstone over night. Check it's PH against your tank's PH. If the PH in your quart is higher, it's not about chemicals, but about getting more O2 into your system... water movement, etc. Stay away from throwing all kinds of chemicals into your water if you have to... in the long run, it's costly to maintain, and in the short run, you could get very unbalanced.
HTH,
~wings~

 

[Anonymous]

Agreed....it may be O2. Those no number alk tests suck BTW. I have the red sea one also and it doesn't hold a candle to a decent KH test. Get a carbonate hardness (KH) test, since this is an issue for you, and use it as your main measure of alkalinity. If O2 is not the issue, then you are surely burning up Alk by precipitating calcium. Your system is young...it may stabalize on its own in a couple of weeks.

Good Luck

 

[Simon1]

Trying the O2 solution now. Will it really take over night to see if this is the problem, or will a few hours with an airstone work?

 

[Anonymous]

Overnight may be overkill, but you get the picture. Do it for a few hours and see if there's a difference. If there is...do it over night to confirm.
~wings~

 

[Simon1]

Ok I tried the O2 experiment, and in just about an hour, my pH was 8.3-8.4! I think CO2 has been causing my problem all along. Thanks for the help, it always seems to be the simple thigs that are overlooked I am rerunning the airstone test to make sure. THANKS

 

[Anonymous]

Just one note on this- I believe CO2 ond O2 do not necessarily displace each other, meaning adding oxygen to the water does not remove the CO2.

However, vigorous water movement will drive out the CO2, so the net is the same in the end.

 

[Anonymous]

Exactly Dan, the point was to think of a natural solution (*more* water movement) rather than dumping in chemicals, which could potentially offset other naturally occuring chemials. We're on the same page.
~wings~

 

[flounderer]

The most practical way to remove CO2 in an aquarium is to add vigerous aeration to strip it out. Water can hold several thousnd times more CO2 than air so CO2 will diffuse from a high concentration (water) to the low concentration (air) and will slowly reach equalibrium. High dissolved CO2 levels transform into carbonic acid leading to low ph. Skimming the surface allows for some gas exchange, protein skimmers should also lead to some gas stripping.