High Calcium, but lower pH and Alk?

[socalchris]

Hi all,

I have a 60g tank that's been up for appx. 14 months.

First parameters:

pH: 7.7-8.0
Calcium: >400ppm
Alk: 5.8-6.1dKh

First, pH:

Multiple test during lights on and lights off period show the same pH? I thought pH was supposed to be lower during light off? Is it possible my pH test kit is bad? It's a Salifert, but there's no expiration date...I bought it from a Marine Depot sale some time within the last six months, so I believe it's new.

Second, Calcium:

I just purchased my Calcium test kit today. (Also Salifert)
I'm not absolutely positive of the exact measurement of "when the pink-red changes to clear blue" This explains why I just wrote >400ppm, which is pretty close to the optimal range, correct?

Third, Alk:

Is my Alk. low enough for me to be concerned?


Perhaps these are newbish questions for someone who's been in the hobby a few years already, but I purchased my first ever SPS frags at LEAST six months ago and they haven't grown much. (Green Digi and a Red Monti) My goal now is to get my parameters within the optimal range and keep them stable enough to see an improvement.

Everything else in my tank is relatively healthy and stable. I have an ATO and a fairly oversized skimmer. Plenty of liverock...soft corals and fish all doing well.

Thanks for any pointers.

 

[HighlandReefer]

Your alk. is low and should be between 7-11 dKH.

What is your salinity level? Salinity for coral should be higher than fish only tanks. I keep mine around 1.0260.

Magnesium can come into play also, if your salt mix is low in it. The range for mag. should be 1250-1350 ppm.

Test kits for pH can be off by quite a bit. I would recommend a two-point calibration pH meter. I would not worry about your pH at this point, until you purchase a good quality pH meter.

 

[socalchris]

<a href=showthread.php?s=&postid=15037414#post15037414 target=_blank>Originally posted</a> by HighlandReefer
Your alk. is low and should be between 7-11 dKH.

What is your salinity level? Salinity for coral should be higher than fish only tanks. I keep mine around 1.0260.

Magnesium can come into play also, if your salt mix is low in it. The range for mag. should be 1250-1350 ppm.

Test kits for pH can be off by quite a bit. I would recommend a two-point calibration pH meter. I would not worry about your pH at this point, until you purchase a good quality pH meter.

I keep my salinity at 1.025. It's pretty consistent thanks to the ATO. As for Magnesium, I don't have a test kit for it and I have yet to test for it. I guess I'll make that my next purchase.

When you say a two-point calibration meter, do you mean something like a Pinpoint? I've been waiting to find a good deal on a used one here.

 

[HighlandReefer]

If this is what you are refering to, then yest this is a good inexpensive pH meter IMHO.

 

[socalchris]

So yesterday I picked up a Milwaukee pH Monitor. It's a two-point and I calibrated according to another thread that was posted here. I used the Milwaukee 7 and 10 solutions.

My ph is showing 7.7 right now...so it looks like my Salifert and API test kits aren't off too much.

I also tested Alk again and it's still low.

 

[therealfatman]

I would raise the alkalinity with some sodium carbonate (baked bicabonate of soda) besides raining the alkan linity it will also raise the pH as it is also to low.

Two Part Supplements by Randy.
http://reefkeeping.com/issues/2006-02/rhf/index.php
There is a two parts supplement calculator on the RC home page. I would use the amount needed to boost the alkalinity to around 10 to 11 using the baked sodium by carbonate as directed in the part two of the old recipe by Randy. The bicarbonate of soda can be bought cheaply in large bags at Sam's Club and Walmart likely as they own Sam's club. Raising the alkaliity 4dKH would also raise the pH about 1.2 units. Therefore I would add only half the recommended sodium carbonate slowly over a period on 24 hours while keeping an eye on the pH. If the pH starts to go above about 8.4 stop adding sodium carbonate and start adding sodium bicarbonate slowly until you reach your desired alkalinity. Remember you will still have to watch you pH as sodium bicarbonate lowers the pH as much as sodium carbonate raises it. In general once you reach your desired alkalinity you can just use sodium carbonate as an alkalinity supplement. Usually only Kalkwasser users need the pH lowering effect of the sodium bicarbonate when supplementing.

 

[socalchris]

<a href=showthread.php?s=&postid=15066936#post15066936 target=_blank>Originally posted</a> by therealfatman
I would raise the alkalinity with some sodium carbonate (baked bicabonate of soda) besides raining the alkan linity it will also raise the pH as it is also to low.

Two Part Supplements by Randy.
http://reefkeeping.com/issues/2006-02/rhf/index.php
There is a two parts supplement calculator on the RC home page. I would use the amount needed to boost the alkalinity to around 10 to 11 using the baked sodium by carbonate as directed in the part two of the old recipe by Randy. The bicarbonate of soda can be bought cheaply in large bags at Sam's Club and Walmart likely as they own Sam's club. Raising the alkaliity 4dKH would also raise the pH about 1.2 units. Therefore I would add only half the recommended sodium carbonate slowly over a period on 24 hours while keeping an eye on the pH. If the pH starts to go above about 8.4 stop adding sodium carbonate and start adding sodium bicarbonate slowly until you reach your desired alkalinity. Remember you will still have to watch you pH as sodium bicarbonate lowers the pH as much as sodium carbonate raises it. In general once you reach your desired alkalinity you can just use sodium carbonate as an alkalinity supplement. Usually only Kalkwasser users need the pH lowering effect of the sodium bicarbonate when supplementing.

Thanks for this info. I did a small waterchange yesterday and my ph is now 8.0 exactly, but that's only as of this morning during my "lights out" period. It should be higher during "lights on", right?

Alkalinity didn't seem to change much, but like I said, it was a small waterchange.

I think I will use the baking soda to attempt to bring up the Alk.

 

[HighlandReefer]

I would increase your alk. using the Chemistry Calculator and baking soda or baked baking soda as Fatman has suggested.

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

FWIW, a pH of 8.0 is fine, particularly in the morning before lights on.