Ph Problems?

[xamy_valox]

Hi, since having a PH crash in my tank a month or so back I added coral sand into my filter on the advice I got given from here and LFS's.

At first this seemed to be working, my PH raised up to around 7.6 (dark blue on the API master tester kit). However, since adding my new filter (to which I added the coral sand) my tank seemed to go through another mini cycle (I did add the previous tanks mature media, but for some reason it did it anyway) my Nitrite levels soared, although my ammonia levels stayed pretty low.

Anyway, due to many water changes and the use of Special Blend (though I have only dosed the tank once with this) I am now back on the straight and narrow with my ammonia, nitrite and nitrate (0, 0, 5). However my PH seems to refuse to climb back up?

I just did a test, left it a bit and it seemed to be back up to around 6.6 after dropping to 6.0, however once I brought the vial into the kitchen to rinse, it seemed to go back to being very yellowy?
Would this be due to all of the frequent water changes I have been doing to lower my nitrites? Will it climb back up naturally or should I add more coral sand to my existing bag? there already seems to be quite a bit though and i don't want to overdo it =\

 

[Aquascaper]

It takes a while for the acidic water to break down the calcium carbonate and raise the pH. As you've done lots of water changes you have removed all the dissolved carbonate that were raising and buffering your pH and will have to wait for more to break down from the crushed coral and adjust the pH again.

 

[xamy_valox]

So should I just leave it as it is and wait for it to raise rather than adding more coral?

 

[elmo666]

What is the ph of your tapwater? If this is low it may be an idea to buffer it before using it for water changes.

 

[xamy_valox]

I have no idea actually! I have never tested it. How would I buffer before adding?

 

[elmo666]

You can use coral sand as in your tank, but this would take a while so would have to be preped in advance. You can get liquid buffers, such as ph up, and am sure there are others. Ph and gh, kh are complex and am not the man to explain it, but to avoid ph crashes the water needs some "resistance", or as we call it, buffering capacity

 

[Aquascaper]

It is never advisable to use chemical buffers as a long term solution and sodium bicarbonate will cause a build up of sodium ions in time which will affect the fish (before anyone suggests it). Allow the coral sand to work and you won't have problems in future if you are just doing regular water changes as the amount you are replacing will not affect the pH adversely. Should you need to change more than 50% in the future obtain so reverse osmosis water from an LFS to do it with.

If your tap pH is significantly different the only safe way to resolve the issue would be to use RO water instead for water changes.

 

[xamy_valox]

I normally I only change about 20% every week, so that shouldn't affect too much I can't imagine?
I think I'll just leave it to do its business now then, and hope it clambers back up. I live in the West Midlands area in UK, and apparently our water is really good PH wise but as I say, Ive never actually tested my tap water for anything!

 

[Aquascaper]

Worth testing a sample straight front the tap and a sample left for 24hrs. You will get two different readings, the sample left for 24hrs being lower usually. As you add tap water straight from the tap this is the reading you should be using to work out the difference between it and your tank.

 

[elmo666]

Aquascapers input has been sound,, I only asked about your tapwater ph incase it was soft and acidic. That said, you should be fine where you are, not many peat marshes in the area lol.

 

[Aquascaper]

It's worth checking to be sure you're not fighting a losing battle but unless there's a big difference the coral sand should be able to buffer it adequately.