Low pH in tank, 7.3 pH

rogersoh · 03-22-2006, 10:28 PM

I would like to share my experience of the tank pH level drop to 7.3 pH when I did some modification to my tank.

I had added a baffle to allow for an overflow system in my 2' x 1' x 1' tank. Put back the sand, and rock from my existing tank to the new tank and let is run with filtration system for a week.

After the tank had stablise, I transfer my fishes (1 Koran Angel, 2 Humbug Damsel and 1 Blue-velvet damsel) + 1 sea urchin ( don't know the species name). 1 to 2 weeks later, the pH level of the tank drop to 7.3 pH, NH4 = 0, NO2 = 0 NO3 between 50 to 100 ppm (not sure the exact value the color of the test shown between 50 & 100 ppm). Note that the tank is operating with 2 external filter only. In the previous tank I had a skimmer operating too, but was damage while I did the modification for my current tank.

Panic, I start to add in reef buffer to increase the pH. I try to increase it not more than 0.2 pH per day. But the level still can't reach to 8.3 pH. The sea urchin is now suffering from the stress. Do partial water change (20%) every 3 days.

I rush to get a new skimmer, make a quick modification of the other tank to make into a sump, a diy overflow pipe. After connecting up the sump, and skimmer I notice the pH level start to increase until now ( about 5 days) the pH reaches 8.1 pH.

IMHO the drop in pH level maybe caused by not enough aeration, led to increase in CO2 level. After I add the protein skimmer there is an increase in the aeration and CO2 is diffuses to the atmosphere thus the acidic of the water reduces and start to go back to normal condition. Hope that the system can manage at that level and my sea urchin can recover from the stress.

I had not test the NO2, NO3 level yet as I need to ask my friend to come to my place to help me see the color of the test result. ( I am partial color blind so can't see the color of the test kit well)

jeepjon · 03-23-2006, 10:15 AM

You sure your test is accurate? 7.3 sounds REALLY low for marine species to survive in...I could be wrong. BUT...you may wnat to try a more accurate test. What are you using? pH monitors are great! (of course, I don't own one...)
-Jon

gwen_o_lyn · 03-24-2006, 07:53 PM

Yeah I agree with Jon- I didnt think a reef tank could get to that level. If you aren't using a Salifert test kit, then I'd be skeptical of the results.

And yes, do make sure your tank is getting proper oxygen exchange or you will have PH problems. If you ever open the windows in your house and "air out" your tank, your PH will increase. I always tell my reef buddies, "I got the windows open to help my PH"

Do you have glass lids on your tank? If so, consider removing them because they arent good for this very reason. Your tank needs to be open and exposed to air.

You can do a little experiment by first testing your tank water, then take some of your tank water and leave it outside for about an hour and then retest the PH.

***Rob*** · 03-24-2006, 11:15 PM

Gwen.. great advice..
getting good air exchange is important.
note, this doesn't mean add an airstone, as that will over do it.
make sure you have a skimmer running as that helps alot, also point a powerhead at the surface to break up the surface as this promotes gas exchange too..

rogersoh · 03-25-2006, 12:41 PM

Thank you Jon, Gwen and Rob for your advice.

I agree the Jon, I am using the Pinpoint pH monitor (electronics pH meter) to check. Initial I do not believe the result. So I recalibrate the pH meter with pH 7 & pH 10 solution. The reading shown as 7.3 pH.

After i had add in the protein skimmer, immediate I can see the pH start to increase. Now it is maintain at 8.12 pH.

In this incident my sea urchin suffer badly, now all the spine had drop off, I don't know whether it is still alive. As it is no longer moving. I can only see the very short tencales of the sea urchin moving with the current. Don' t know whether it is the water movement or the sea urchin is still alive. I will be monitoring the condition of the sea urchin closely.

Yes i have the glass lid, I will remove it now to improve the air exchange. My sump is without the glass lid, the air exchage at the sump level is very good and the protein skimmer also help.

I will go and get a new power head and will also point my current pump discharge up the water level to improve the air exchange.

Hope that the sea urchin can survive through this ordeed.

Roger

***Rob*** · 03-25-2006, 04:01 PM

keep us updated, but it sounds like you are on your way to correcting the issue..

Scott · 03-25-2006, 09:35 PM

I really need to get me one of those pinpoint monitors...so much better than trying to match colors with a test kit.

jeepjon · 03-28-2006, 05:43 PM

Yeah....seriously...except in a good reef tank, the pH probe can attract corraline algae...

You mean you don't leave yours in continuously

ops:

ops:

Whoops! ! !

(had to get on the smiley bandwagon)
-Jon

rogersoh · 04-03-2006, 11:27 PM

Latest update:
I manage to test the parameter with my friend help:
NO2 = 0.5 ppm (I immediately to a partial water change at night, not sure of new reading, need to get my friend to check on the color) must have feed too much
NO3 = 50 ppm
pH = 8.13 pH (using electronics pH meter, this I can check everyday)

My sea urchin had die. The rest of the fishes are doing very well.