04-13-2006, 12:59 AM
Join Date: Aug 2005
Location: Bialystok, Poland
The only tap water parameters in my region I know are mainly Ca and Mg levels:
Ca = 55 ppm
Mg = 15.5 ppm
NO3 = 10
PO4 = 0.1..0.25 ppm
Unfortunately, other elements are unkown. In the past I used tap water mixed with RO one in 1:1 ratio. Most of my plants grew quite well apart from Cabomba Caroliniana. Now I began to use only RO water reconstitued as follows:
Ca = 20 ppm (12 ppm Ca from CaSO4, 8 ppm from CaCl2)
Mg = 5 ppm (anhydrous MgSO4)
NO3 = 10 (dosed from Ca(NO3)2 )
PO4 = 1.0
NO3 and PO4 levels are kept at levels given above all the time.
The problem with using CaSO4 is that it adds much SO4 and I really don't know how it affects plants.
That's why I try not to add more than 20 ppm Ca. I was told not to care about SO4 but I donn't know how it will affect my plants.
Now I have to wait and see how plants will behave in such conditions.
When I started to use RO water something's wrong happened to Rotalla Wallichi and Bacopa caroliniana - they grow very, very slowly. The only positive thing with Bacopa is that it looks very healthy. Rotala pracitally "stands still" and its tops are being stunted and "burned" all the time. Maybe the problem concerns Ca/Mg. I'd like to increase Ca up to 30 ppm and see the effects. Lately I've discovered how to dissolve CaCO3 without using CO2.
Namely, one can buy CaCO3 in 1..3 mm pellets form.
You can put some pellets into a tubing (diameter about 3..7 cm). Obviously the bottom of the tubing should be clogged with something that will protect the pellets against falling out (a piece of sponge etc.)
Then, simply put RO filter outlet pipe into the top of the tubing allowing RO water to flow slowly through CaCO3 pellets put in the tubing. RO water will flow out from the bottom of the tubing and collect in a barrel. The longer the tubing and the bigger amount of CaCO3 the higher level of Ca will be. In order to further increase Ca to higher levels (when the barrel is full) one can use small pump to pump water in a closed circuit in the barrel through the tubing.
I carried out an experiment and allowed RO water to flow through a container filled with several grams of oridinal CaCO3 and I achieved GH = 2. This is low because CaCO3 in its typical "sand" form is not well water-permeable and the most of water didn't flow through it.