PH Issue

Bicarbonate of soda will help to raise your water hardness and stabilise the pH. Dose it at 5 grams per 25 litres of tank water. When I started my cycle my pH was 6.6. Using bicarb at the dose mentioned got me up to around 7.5 where it has remained. I also added marine gravel to my tank to help keep it there. How long has the crushed coral been in the filter?

Hi Sue and Paddyc,

My pH from the tap is 7.5, and the same when left for 24 hours, it only seems to fall in the aquarium! This happened during my cycle when i did a large water change because of nitrite/nitrate levels, but i cannot understand why it has happened now as the bacteria were not doing anything (so to speak lol) and now i'm really confused how to get past this point?

If i have to do a large water change (like at the end of the cycle to get nitrate down/bicarb out) how can i keep enough buffer in the water to prevent the crash that happens without killing/stunning the bacteria and putting me back to square one? I don't have a problem with small regular water changes once i have fish, but at this point i don't see how i can even get fish!

I only put 10 grams of bicarb in the tank last night, just to halt the drop as i thought it would be ok for the fish, if i add more ammonia now to keep the bacteria alive, that will increase the nitrates....which means i will have to change the water again...which means my pH will drop....and the circle continues lol

The crushed coral has been in the filter for 3/4 weeks in think, but i have not noticed any change to my water parameters, the only way i have of measuring kh/gh is with test strips and prior to the water change (with bicarb/coral in the tank at the end of the cycle) was KH 3 GH 8 pH 7.2 temp 25c.

thanks Sue, i nearly made a fatal mistake today!! I went to the LFS today to get my water tested, and got talking to the chap in the shop and explained what was happening, and left £12 lighter with a bottle of API proper pH 7.0, convinced that this would solve all my problems, even though i have read all over the place NOT to use these things! I pondered this "solution" for a few hours and decided against it, then checked on here and saw your last reply, now that is the way i am going So emptied the tank, filled it back up, left it for half an hour and tested the pH....7.2! again i scratched my head...how could it drop so quickly? so i tested the tap water...7.2! no idea when this happened! Since i started in January the tap water has been 7.5!

Anyhow, i have taken a cupful of water out the tank and will test this against the actual tank water to see if they are the same...if it's falling in my tank whilst that remains stable, then it must be the tank or something in it?

Following your suggestion, i have not added any ammonia yet and see what the pH is tomorrow, just out of interest (and possibly future practicality lol) how do you keep fish in a tank with no nitrogen cycle present? (if pH is to low) is it a question of just changing water more often?

Thankyou again, i don't think i would have made it this far without your help.

Tony

Although the bacteria in the tank prefer a high pH, they aren't killed by low pH. They just multiply slower. And we want them to multiply fast during cycling so we can get fish.

I have read posts on another forum by someone who has pH lower than our test kits can go. He keeps fish with no problems. What he does is to cycle a tank with the pH raised with bicarb. Once the cycle has finished he then does small water changes to gradually remove the bicarb and allow the pH to fall. During this time he adds ammonia to feed the bacteria (1ppm every couple of days). As the pH drops, if he finds that ammonia is not being converted right through to nitrate in 24 hours, he pauses and continues with the cycling method until he does get two zeros 24 hours after adding ammonia. Once all the bicarb has gone and the pH has dropped as low as it is going to he then adds 3ppm ammonia to check, and if he has double zeros next day, he gets fish; fish that like very soft, very acid water.

There is another approach to take. Rather than use a chemical that increases pH, use a chemical which adds hardness to the water in a more natural way - remineralisation salts. I can't remember if I have mentioned these before, they are used by people who use RO water because they have very hard water and want soft water fish, or they have very high nitrate and want nitrate intolerant fish etc. The salts contain the same minerals that occur in water in nature. The most common brand in on-line shops is Tropic Marin - but be careful as they make a marine version as well as freshwater. You'd also need a GH tester.
With these, you would add enough of the salts to the tank to raise the hardness and pH to the desired value. In your case, I would suggest not trying to turn the tank into hard water, just enough to raise the GH to 4 or 5 german deg. You would also have to add the salts to the new water at the same dose rate at every water change to keep the hardness of the tank constant.
You would  need to always keep a spare pack of salts in the cupboard in case you ever have to do a lot of emergency water changes.

Any updates Knight?