Wierd KH?

[RichReef]

So now that my tank is doing well nutrient wise I've been moving towards others parms. All are good except for PH and KH.

Tested my PH using 2 different brand kits and came up with 7.8.
KH was 6.

So I ran my skimmer intake outside the house. 2 days later PH is 8.1. KH was 5.

Rechecked using 2 different brands kits API and Salifert and a new water sample. Same.

Waited another day. Same.

Does this seem a little strange?

Something seems off.

I have some Seachem Reefbuilder for KH but won't that raise my PH?

Ca 500
Sal 35
Mg 1450
PH 8.1
KH 5 ??

 

[RobZilla04]

With an increase in pH most folks find increased usage of available KH. If you can maintain the higher pH, adjust dosing of KH to balance. You might just see faster growth rates

 

[nereefpat]

7.8 pH is perfectly fine. Running the skimmer intake outside increased pH to 8.1. That is even better.

The skimmer won't have anything to do with KH (german carbonate hardness, which is alkalinity) though. Your tank is using alk (kH), so you need to use something to raise alk...like baking soda, washing soda, limewater, or your seachem reefbuilder. I wouldn't worry about the seachem reefbuilder raising pH. Just use small doses, and the pH effect is temporary.