General Hardness Out Of Control

[Cranky clown]

Twelve months ago I moved to a new house with concrete rainwater tanks as our only water supply. After the first three months I noticed that the general hardness was climbing to unacceptable levels. I cut back the add rate of salts to both tanks, but it still seemed to increase. For the last three months I have been doing usual water changes with no added salts, and still it climbs. The cichlid tank is now at 400ppm, the community tank at 280ppm. I am adding nothing at this stage apart from de-ioniser.

The tank water tests at 15 - 20 ppm. Have always used rainwater before, but it was stored in plastic tanks. Could it be the concrete? When I asked my aquarium store he looked at me like I was insane. Never heard of the problem! Couldn't even direct me to a product to soften the water. Any suggestions? Am thinking of importing town water, but that would be a major pain.

 

[cujoho78]

Hi. Yes, concrete will definitely do that. Over time i imagine that it would decrease if the water is replaced enough. Eventually much of the minerals will have leached out into the water and so the GH and pH wouldn't be so high.

 

[CFC]

Yes, this is why concrete ponds have to be fiberglassed or painted with a rubberised paint to seal the concrete in, i wouldnt imagine the water would be very healthy for drinking either!!

 

[Cranky clown]

Ok, so the rainwater tank appears to be the problem, any suggestions on getting the hardness down? Checked out some local streams on the weekend, but they are all rather turbid after recent rain. Shame, they're normally crystal clear. I do have an above ground, vinyl clad pool which has had no chemicals added since March. Several hundred tadpoles seem to be enjoying it. Do think that water would be ok? Trouble is I live miles from any mains water, and it tends to be rotten with chlorine and flouride. I know Prime treats the chorine, what about flouride? Thanks for your previous replies.

 

[mr.dark-saint]

Got to love free water from caches of "cisterns". Basically with the water sitting longer in there (without replenishment) the cement is leaching out.

The thing is keeping critters from living in the water (since they poop) and then you add that in to your tank which is what you're trying to do in the first place.

With your problem Cranky this is what I would do. For the cistern I'd drain it, dry it, then seal it (most hardware joint can order the stuff you'll need). Or start keeping Rift Lake fish . Water softerner for the whole house may be in order? (Without any change to the cistern). Revers Osmosis unit would be another thing to think about. Or get another plastic rain collector.

 

[confusion]

is getting an RO unit an option for you?