Believe it, or not?

[onux20]

Good morning everyone. Just wanted to bounce a problem off WAMAS Nation.

 

I bought ph monitor a few weeks back and have been generally happy with the results. Over the past week, I had noticed a rise in the tank

[ReeferMan]

I dont think the ph monitor was way off from when you calibrated it. IMO 7.9-8.1 swing is good. 8.2 is ideal

[Brian Ward]

Good morning everyone. Just wanted to bounce a problem off WAMAS Nation.

 

I bought ph monitor a few weeks back and have been generally happy with the results. Over the past week, I had noticed a rise in the tank's Ph. I decided to recalibrate the monitor to make sure I was getting an accurate reading.

 

I powered down the system to do my weekly water change, ph ~8.14. (early am). Calibrated the ph monitor and powered up system (20-30 min later), Ph ~7.96

 

At this point I was not too worried. By mid light cycle it was still in the 7.X range. The fish, snails, emerald crab, cleaner shrimp, don't look stressed or anything. Scylomia and poccilpora (sp?) don't look as they did the day before the water change. Not dead or visibly dying...just not as happy.

 

One major change that happened AFTER the water change was the creation of a small fuge using macro and DIY light. (Thanks again Brian Ward) I put that on an alternate light cycle from the main tank as to minimize ph swing.

 

When I get home from work, I always give the tank a quick look over, and the ph was still in the 7.X range, 3-4 hours in to an 8 hr light cycle. I added Kalk to the top off water yesterday afternoon. By 9pm the ph was 8.14. I checked it again this morning and it was still around 8.1. I'll see what it looks like tonight when I get home.

 

A lot of info to get to the questions.

Should I believe the reading on the ph monitor? The test kits are hard to get a good reading...hence the monitor.

What would cause ph get and remain depressed?

How do I get it back up long term? Kalk addition is short term right?

 

Ron

 

 

Constant kalk addition is good for keeping pH up, though with the size of your tank you may not be adding enough kalk to keep your alkalinity up. For nano tanks, 2-part is frequently a better solution since you aren't as constrained by your evaporated water volume. You do need water changes to buffer your water but this doesn't sound like your problem. Be sure your alkalinity, calcium and magesium levels are correct. Look at your bioload as well as surface aggitation for gas exchange - lower than normal pH can be caused by a build-up of CO2 that isn't being exchanged for O2. The chemical test kits are always the most accurate - the pH probes are convenient for daily monitoring but you need to back up your results with the periodic chemical test.

[onux20]

I dont think the ph monitor was way off from when you calibrated it. IMO 7.9-8.1 swing is good. 8.2 is ideal

In hindsight I would agree. The problem is getting the ph back above 8.0 and keeping it there. Hopefully dosing the kalk yesterday did the trick.

Ron

Edited May 29, 2008 by onux20