PH problems

[crenny]

Had tank going on about 7 months. i let my nitrates get a little high so i did a 30 gal water change out of my 75 gal and cleaned the canister filter for the first time. ever thing was cool nitrates still high. mixed up 30 mor gal but this time i syphond half the tank, this is about 5 days latter. with in two days my tank started to cycle again. It was a small cycle nothing got toxic. But now my fish got ich. so i treated with copper safe made fom mardel and i put that slime stress coat stuff in the tank. Now my PH has fallen to around 7.4,7.8 ive added Araga Milk, RedSea buffer for the last two days and im getting nothing over 7.8 and ive never had a problem befor. Ive use or/di water have 60lbs crush coral 60lbs live sand. Does anyone know what the problem is? Turned on the skimmer to take out the stress coat today maybe that will help?

 

[barry cuda]

I'd be more concerned about the ich and copper than the low pH. 7.4 is pretty low, but if you're stable at 7.8 now, that's high enough as long as you don't get large swings. Are you testing at the same time every day? PH tends to drop overnight and rise during the day due to photosynthesis by algae. My main tank held at 7.8 for months before I started testing for alkalinity and found out it was very low...I've been slowly bringing alk up and pH has been rock solid at 8.2 for a couple weeks now.
A 50% water change is pretty drastic and it seems likely to me that it can upset your chemistry, on top of stressing the inhabitants. I don't know if the copper and stresscoat will affect pH either. PH is more useful as an indicator of other problems, as I have always understood it. Possible causes of low pH include:
1. Low alkalinity
2. Poor oxygenation, leading to high dissolved CO2 levels
3. Lots of other things I either don't know about or can't think of
I'd be keeping an eye on your alkalinity and make sure you have plenty of gas exchange (remove any glass covers, keep the skimmer going and possibly aim a couple powerheads at the surface to create turbulence).
One thing you should know - unfortunately, you'll probably never be able to keep inverts in that tank again. Copper adsorbs onto every surface in the tank, especially the seals, and can't be removed. That's one reason the experts here (not me, certainly...I'm just parroting their advice) suggest using a quarantine/hospital tank.
Just how high were the nitrates? Unless you were at seriously dangerous levels, reducing them gradually with a series of smaller water changes might have been easier on the tank and livestock.

 

[reefeel]

I had the same problem but it wasn't from too little oxygen or too little alkalinity it was from my calcium being so high, up in the 1,000's. So I switched off of Oceanic salt back to Instant Ocean since that was when the problem started to occur. Test your calcium if it seems that there's plenty of oxygen.

 

[reefeel]

PH tends to drop overnight and rise during the day due to photosynthesis by algae. My main tank held at 7.8 for months before I started testing for alkalinity and found out it was very low...I've been slowly bringing alk up and pH has been rock solid at 8.2 for a couple weeks now.
What do you use to raise your alkalinity? I use buffers but they never go beyond 8.00 at around 2pm and then my pH is about 7.8 at 7 am. Is that swing harmful for my fish.

 

[clarkiiclo]

The nitrates are probally coming from the crushed coral. Is your tank half and half or is it mixed in with the sand?

 

[jacknjill]

did you dump the copper in your display tank?

 

[barry cuda]

Originally posted by reefeel
What do you use to raise your alkalinity? I use buffers but they never go beyond 8.00 at around 2pm and then my pH is about 7.8 at 7 am. Is that swing harmful for my fish.
As I understand it, that swing is fairly normal and is actually not unlike that found in a lot of reef areas in nature. Someone more experienced than me (Bang? You listening?) can probably give you better info, though.
I started out using Kent Marine Pro Buffer and have switched to a homemade mix of baking soda and washing soda, under the guidance of someone from my local club who's been doing this a lot longer than I have. I'm trying to be conservative in how much I dose so as not to bring alk up too much too fast. So far I've brought it up from 5 dKH to 8, and I'm not *quite* done yet. I use Oceanic salt and my Ca is off the scale, so I need to bring alk up a little more to achieve something resembling a balance.

 

[crenny]

sorry worked 12 hour days all week. The fish are doing real good. The ich is gone no more white spots. The PH is up to about 8.0 as of 5:00 tonight, nitrates are about 60. so the crush coral gives the tank high nitrates, it is mixed 50/50 live sand. And i did mix the copper in the display tank. It was a fresh water tank for years and i had treated those fish a couple times be for, so the copper was allready in the tank. Does that men i can never have a reef setup in that tank someday?