Is Low carbonate hardness a problem?

[MikeLowndes]

I live in a hard water area. For about a year I’ve run my 50l tank on filtered tap water. I’m doing partial walstad/ ecosystem so no CO2, no major water changes and lots of plants in good substrate. But the general hardness crept up to 14 deg. At which point I started to lose the odd fish ( i know may be correlation not causation). Nitrates never get over 20 or so and I feed iron in via API Leaf Zone every month or so.
I’ve since then slowly brought general hardness down to 9 over a couple of months using distilled and rainwater. I intend to try and hold it about there. pH is a flat 7 consistently.

However I now note that carbonate hardness is very low. - 1-2 drops or about 40 ppm. Aqualog is telling me this is a problem and it should be over 70, but some posts on here (I am now unable to find) have said it’s not so much a problem. What’s the consensus? I do note that snails grow slowly in the tank - generally a good thing IMO.

Mike

 

[MichaelJ]

However I now note that carbonate hardness is very low. - 1-2 drops or about 40 ppm. Aqualog is telling me this is a problem and it should be over 70, but some posts on here (I am now unable to find) have said it’s not so much a problem. What’s the consensus? I do note that snails grow slowly in the tank - generally a good thing IMO.

No, it's not a problem. As a matter of fact most of us around here keep our alkalinity (dKH) very low to in order to gain beneficial acidity levels (pH a fair bit below 7) in our planted tanks. I can only really think of one scenario where higher levels of alkalinity is desirable and that being if you keep livestock that prefer above neutral pH - such as certain livebearers, African cichlids, Rainbow fish and fish that are adapted to more brackish waters.

Cheers,
Michael

 

[dw1305]

Hi all,

I live in a hard water area. For about a year I’ve run my 50l tank on filtered tap water. I’m doing partial walstad/ ecosystem so no CO2, no major water changes and lots of plants in good substrate. But the general hardness crept up to 14 dKH

I'd just change a bit more water. Diana Walstad herself now advocates both some water changes and some water circulation. The links and details are in the thread is <"Walstad revises">.

I’ve since then slowly brought general hardness down to 9 over a couple of months using distilled and rainwater.

I have hard water and I am a rainwater user. If I didn't have access to rainwater I'd use tap.

However I now note that carbonate hardness is very low. - 1-2 drops or about 40 ppm. Aqualog is telling me this is a problem and it should be over 70....

What the others have said.

Cheers Darrel

 

[MikeLowndes]

Hi all,

I'd just change a bit more water. Diana Walstad herself now advocates both some water changes and some water circulation. The links and details are in the thread is <"Walstad revises">.

I do use circulation via an external filter - mostly biological but I also skim. I’d say I replace about 15% water per month on average through vacuuming up dead plant material and topping up. Thanks - I’ll have a read of the revision stuff - I’m not trying to keep a stagnant pool lol but also don’t fix what ain’t broke if plants and substrate are removing nutrients and other toxins effectively. It’s the concentration of hardness and lack of carbonates that concerned me.

 

[dw1305]

Hi all,

I’d say I replace about 15% water per month on average through vacuuming up dead plant material and topping up.

but also don’t fix what ain’t broke if plants and substrate are removing nutrients and other toxins effectively. It’s the concentration of hardness and lack of carbonates that concerned me.

If you change a bit more water then that you should replenish the alkalinity (carbonate hardness). Nitrification will use up <"some of the carbonate hardness">. I use regular small volume water changes, because it <"suits my morning routine">.

also don’t fix what ain’t broke if plants and substrate are removing nutrients and other toxins effectively.

Plant health looks fine in <"your other thread"> and plants are really effective at maintaining water quality, but I still see them as an <"adjunct to water changes, not an alternative">.

At which point I started to lose the odd fish ( i know may be correlation not causation).

I'm a great fan of <"if it ain't broke don't fix it">, but I think that changing some water may improve matters.

cheers Darrel