confusing water perameters and ridiculous test results

so i have a little ebi nano tank with redsea florabase as a substrate sponge filter and the internal fluval filter it came with. no fert dosing or co2.
I tested my water and my results were

ph-6
gh-11 ?
kh-4
temp-68

i just use dechlorinated tap water.. my gh and kh were never this high when i was using the fss so could it be the substrate?
im using the api gh and kh testers and am wondering how accurate these are. is there a better way to test my tanks hardness? input is greatly appreciated.

I've found the API GH and KH tests to be pretty consistent and accurate, as long as the test chemicals aren't past their use-by date.

That said, I do find it interesting that your GH was raised so substantially (presumably by the substrate).  What is the GH of your tap water?

a whopping 3 gh straight out of the tap.. so this problem is most likely from the substrate? and i figured if my gh was so high wouldnt my ph be higher as well? it is pretty consistant at 6. the aeration from the sponge filter wont effect that also will it?



edit: i also just tested another tank i have (3 gallon) with the same substrate only running a little hob with ceramic rings and my gh came out at 6! and this one i do dose a little bit of microbe lift all in one bloom and grow.

PH is related to KH, but not GH.  The organic matter in the substrate has overcome the alkalinity of your water (KH) and is pulling it down into the 6 range.  Substrates like this and amazonia do this by design - they produce lots of ammonia which gets nitrified and thus acids are produced by the cycle that pull the PH down.

It shouldn't be raising the GH that much, though it's certainly possible.  GH is generally calcium and magnesium ions, among other things.  Substrates can affect GH greatly.  How many water changes has the tank seen since you added the substrate?  The elevated GH may taper off with time.

Aeration will cause CO2 in the water to off-gas, thus causing the PH to rise somewhat. This doesn't affect the GH or KH.

hmm.. i mainly do top offs as my shrimp have been really sensitive since i changed the substrate to the florabase from fss. (terrible idea as it killed off tons of shrimp) i may do more very slow water changes through out the week to see if it drops some.

Yeah, I've had a pretty big die-off in my blue velvet cull tank recently that seems directly related to artificially boosting my GH from 5 to 12 (snails and platy fry). It could have been something else, but I'm pretty sure it was the GH boost.

I would do some careful larger water changes (so as not to disturb the substrate) and see if that helps. What kind of shrimp are in the tank?

well as of right now the only shrimp are some cherrys, 2 bv :/ and one crs. lol.. before the switch i had a thriving community of rcs and tigers... really messed up my tank it seems. haha plus i had bought some shrimp from an online site and stupidly put the water the shrimp came with into the tank and it brought hydras and destroyed alot as well.. things are slowly rebuilding despite my high gh.

Cherries should tolerate the higher GH; mine have. But they prefer it to be a bit lower, I think. CRS definitely prefer it lower.

I had hydra infest two of my tanks a while back; they road in on plants. I used powered dog de-wormer to get rid of them - worked great and didn't kill anything else, but you have to use a really low dosage.

Substrates designed to monkey with PH (FSS, florabase, amazonia, etc.) can be tricky, especially early on. I haven't heard of one raising GH like yours has though. Maybe it's more mineralized than the others are.

Yeah everyone I have read reviews from said it didn't raise their gh that high so I have no idea especially if I'm not dosing and my tap comes out fairly low

Hopefully a few water changes will clear it up.

I will post results later today.. Going to stop by Clarks in Bellingham to make myself feel better LOL