Water testing numbers not making sense-

[jaxredsoxfan]

So I do a 15% water change on my Red Sea max-e 270 (70gal) every 9 days using Instant Ocean Reef Crystals. When I do this I usually do a set of water testing. Last week I noticed my PH had dropped from the normal 8.15-8.2 to 8.05. Today I did a full battery of tests, and am a little puzzled with results:

temp-78.7
Sal- 1.025
PH- 8.02
Alk-11.5
NH3-0
NO2- 0
NO3- <5
Ca- 539
Mg- 1160
PO4- undetectable

Hanna checkers for ALk, Ca, PO4
Red Sea kits for all else.

Not sure how Alk could be 11.5 and PH 8.04. Also not sure how Ca could be 539. I do dose Bionic 2 part at 13ml of each per day. Everything looks good and no visual bad signs in tank. Should I be concerned with these readings? I am thinking individually not bad, but would like to get the PH back up to 8.2- but dont want to raise Alk any more than it is, and not sure if this is indicating something is trending bad. Any thoughts would be appreciated.

 

[JakeLikesReefs]

Adjusting or dosing alk with the goal of PH change is a losing battle. Id probably raise your mag a bit toward 1400.

As for you pH, oxygenation of the water is the goal. Things like running a skimmer or having a fuge will help your pH long term. Randy has a great write up about pH.

Thanks,
J

 

[jaxredsoxfan]

Thanks Jake. Don't think its oxygenation as its an open top tank with 3 returns and 2 tunze powerheads. I'm thinking maybe running a CO2 scrubber on my Skimmer air line.

 

[Mastiffsrule]

Hello

My take on it is your numbers are fine. I would not chase the PH number so much. It’s gonna swing depending on time of day, weather outside and in the house, etc. As mentioned maybe dose some mag.

I am thinking the water changes are raising the calc and alk. Reef crystals will have a bit higher nutrient make up than regular IO, hence the reef in the reef crystal. (Their marketing people really spent time naming that salt, huh ) anyway if you are dosing, and doing the water changes you intake of calcium and alk may not be keeping up.

If everything looks fine and dandy, I say keep doing what you are doing. Just make sure alk doesn’t sneak up on you.

 

[SeaDweller]

Yep. Your alk is high cuz of the salt mix. Ph flux throughout the day and respiration, photosynthesis, available O2, CO2, etc and your Ca is high cuz of the salt mix too.

 

[jaxredsoxfan]

Thanks guys, do you have a recommendation on a better salt mix that would keep numbers more in line?

 

[SeaDweller]

Thanks guys, do you have a recommendation on a better salt mix that would keep numbers more in line?

It depends. What levels do you want to keep? I like to keep things close to NSW levels now, so I use Tropic Marin Pro exclusively. It’s pricey but keeps the levels I want, or a close second would be regular Red Sea salt. My main concern is dKh. I find a salt that makes it so I don’t have to adjust it much and matches the goal I have in mind, and TMP has every other number in line, so I’m good there. I try to maintain dKh of no higher than 8.0 so I have to adjust TMP (alk is usually 7.2-7.5 dKh) with some baking soda.

You can even use something as inexpensive as regular instant ocean and adjust the alk down with Seachem Acid buffer or muriatic acid, and maybe adjust Ca up or Mg if it’s too low.

For most people, I feel TMP, regular Red Sea salt or Brightwell’s NeoMarine (haven’t used it yet, but the parameters are nice) would fit the bill perfectly. Even Live Aquarius’s salt (aka Fritz RPM) would be an ok choice, but I get alk higher than they used to advertise (they used to advertise 8.5, but now it’s a range of 8.0-9.5 or something like that).

I’ve seen successful tanks with all types of salt.

 

[Randy Holmes-Farley Verified Community Expert]

Not sure how Alk could be 11.5 and PH 8.04. Also not sure how Ca could be 539. I do dose Bionic 2 part at 13ml of each per day. Everything looks good and no visual bad signs in tank. Should I be concerned with these readings? I am thinking individually not bad, but would like to get the PH back up to 8.2- but dont want to raise Alk any more than it is, and not sure if this is indicating something is trending bad. Any thoughts would be appreciated.

pH is determined mathematically by alkalinity and the carbon dioxide level. Homes with elevated CO2 usually have lower pH than expected for equilibration with normal air.