High Calcium / Low PH / Low Alk - Question...

eohlin

New member
So...here's what I have...looking for some advise....

75 Gallon mixed reef..mostly softies and LPS.

Salt mix has been Oceanic...just finished raising it from 1.019 to 1.025 over the course of 14 days or so. Been adding plain RO/Di water for 4 days now.

PH fluctuates between 7.77 and 8.1 as measured by an APEX calibrated probe.

Temp is between 77 and 80 degrees over the course of the day.

Calcium has been over 500 for the past week or so...I think this is due to adding fresh saltwater instead of RO water to increase my low salinity. I test the calcium with a Salifert test.

Alk has been as low as 6.7 on 4/17 and as high as 7.7 on 4/20...it's 7.5 today.

Mag is around 1320...tested on 4/17 as well.

I think my PH is a bit low, from what I read, I want it around 8.2 or so...and ALK is a bit low as well...target around 9 or so for that...right? I'm thinking, because my PH is a bit low and my ALK is a bit low...my calcium is not getting used up as much by the coral. Is this correct?

I have BRS's two part...but I surely don't want to dose any Calcium, seeing it's somewhere over 500. I think the correct thing to do would be dose some ALK (bought recipe 1) to get it around 9 and watch what the PH does.

Opinions / thoughts / suggestions would be much appreciated!!

Thanks,
Eric
 

ANGRY JOHN

New member
that depends on what you want for alk. those that carbon dose would say that your alk was just right, your around nsw levels, do you want a higher alk and why?
 

disc1

-RT * ln(k)
You can use recipe 1 to raise alk and it will bump you pH up at the same time. Just go easy on it, don't try to get there all at once.
 

bertoni

Premium Member
It's okay to dose just the alkalinity part in this situation. It might improve the pH a bit, but the cause of low pH in an established tank is carbon dioxide. Most houses are closed up enough at least part of the year for a carbon dioxide buildup to be common.

The range you gave likely is safe enough. If you want to raise it, fresher air or a limewater drip might help.
 

eohlin

New member
I have the tank in my home office....working out of it most days.

I also have a fairly powerful computer that generates some heat...I typically open the windows for several hours every day just to keep some fresh air moving. I have no covers over the tank...with a ceiling fan running most of the time.

How can I check if it's excess CO2 that's causing this?

Everything seems to look good in tank...I'm not sure it's worth worrying about, but I'm just not sure.

I also have a ton of water movement across the surface of the water. There's a spray-bar type return on this tank...does that help or hinder the PH....I'm sure it helps with the oxygen exchange.

What else can be done to raise the PH levels?

Thanks,
eric
 

bertoni

Premium Member
Well, the only alternative to carbon dioxide is measurement errors. Either's possible, but the range you give seems fairly normal for an indoors tank. Does the water surface have a lot of motion, like some good waves rolling around? That agitation can help break up surface films and help a lot with aeration.

The spray bar should be find. Is it under water?
 

eohlin

New member
The spraybar is underwater...there are holes drilled at different angles to direct the water.

There is a lot of surface movement across the entire length of the tank. There was so much, I actually rotated the spray bar down a bit last week to stop the splashing!

eric
 

bertoni

Premium Member
Okay, that sounds good to me. I might try leaving a window open a bit one night when the temperature is appropriate. Mostly, I wouldn't worry much.
 
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