Help! Dramatic drop in pH

[limemittens]

Over the past few days we have noticed a dramatic drop in our pH levels of our 65 gallon tank. Nitrite is .25ppm, Ammonia is 0, pH has dropped from 8.2 to 7.4 in two days, and we have been trying to drop out Nitrate levels from 80 ppm for the last week by doing 20% water changes.

Has anyone had problems like this and how can we raise our pH so the fish don't die? We added buffers and pH increaser as soon as the problem was noticed but the fish are looking pretty bad. Also welcome advice on reducing the the nitrate levels.

65 gallon tank
1 yellowtailed damsel
1 blue damsel
2 peppermint snails
3 hermit crabs
3 green chromis
2 three stripped damsels

200-250 lbs live rock
3 inch live sand bed

 

[quarryshark]

What are the water parameter(including Akl) and temp. Also, do you have a glass cover on the tank? How much water circulation? Any PH's pointed towards the surface?
Welcome to AA!!!
I'm in the next town over...Brunswick.

 

[limemittens]

Thanks for the welcome. Small world!!! lol

Don't know about the Akl but the temp has been a fairly constant 78 degrees throughout all of this. We have not been measuring the Alk much but maybe we should. We have a conventional hood on our tank with one halogen light and one anemone light. We normally turn the lights on during the day and then off at night. Circulation has been good. We don't have powerheads towards the surface (Would this help? Doesn't seem that way but you never know). We have a Fluval 304 filter system. The tank has been established for about 3 years but new fish were just added recently. In the last few hours the fish seem to have gotten their color back but they are all still swimming near the top and breathing fast.

 

[quarryshark]

No glass hood? Try pointing a PH towards the surface to up the gas exchange and do some water changes. IMO water changes are your best weapon. Do you use RO water?

 

[limemittens]

Update:

We don't really know what to do..but have tried something for overnight to get the fish out of such harsh conditions. We have gradually qt them to a 5 gal aquarium with more normal levels of pH for the night. The booster seemed to helping but such large amounts were needed that we ran out. Inside the smaller tank, they seems to be doing better. They are swimming and seemed to calmed to normal. We lost two of them but hopefully we can get the pH back up tommorrow and start to add them back into the bigger tank. If anyone has any suggestions though, we would be so ever grateful.

 

[limemittens]

We do have glass on the bottom slide of the hood..... We do use RO/ID water. We will continue with the water changes and point the powerhead up to see what happens. Saving the fish have been our main concern. Planning on heading to Aquatic Tech in Columbia Station in the morning to get some advice and get more pH increaser/ Alk booster. Thanks so much for your help and if you can think of anything else let us know.

 

[quarryshark]

Open the glass hood to help with gas exchange too. In fact, consider replacing the glass with eggcrate to overall give you better exchange. I bet the PH will come up some. The boosters give you a temporary fix, but you really need to find the cause.
Tell Greg at aqautic tech that Kurt said hi.

 

[jaiden]

Try another test kit.. maybe at your LFS. this sounds weird...

 

[limemittens]

Thank you

Kurt,
Just wanted to thank you for all your good suggestions and advice. So far the gas exchange seems to be the problem. After leaving a powerhead towards the top all night and the hood open, the pH is back up to about 7.9 and strangely our nitrate has dropped by about half. (This seemed weird to me but I tested it with two different testers and it still was about the same.) Fish appear to be doing well and swimming happily. We are going to keep testing throughout the weekend to ensure everything is good and the pH stabilizes.

Question: We do not have a protien skimmer currently as we were told we would not need one for a FO tank. After reading several posts on this forum, it seems some people are using them. Would adding a protien skimmer be a good investment to inprove circulation and oxygenation? Can you recommend a good one for a 65g?

 

[quarryshark]

Its weird how that works isn't it.
Yes a skimmer is a great investment. Aquatic tech has an excellent selection.
Do you have a sump, or do you need to use a HOB?