For outside setup, we use stock tanks filled with pond water and 1500 watt stock tank heaters with thermostats, wrap them with insulation and cover with clear plastic over hoops if the air temperature is expected to drop under 50F (10C). The outside setup allows us to add fish, snails and other plants for better balance and to create a small flow of fresh water through the tanks. Details
Especially in aquariums, we recommend a minimum 25% exchange of water twice weekly to avoid the buildup of unwanted minerals or excessive hardness. At all costs avoid using water that has passed through a water softener or from a well with salt intrusion. Water pH doesn't seem to be an issue nor does algae -- algae bothers people more than it bothers the plants.
Replenishing Water in an Aquarium by Chris Lindsey
In 6 to 12 days from germination, healthy seedlings have their filiform and hastate leaves as well as roots and this is when we plant them. We plant in three ounce plastic cups with holes poked in the bases and use orchid basket wire to make small pins to anchor the seedlings.
We plant in plain sand dug from a hole on the dune on the ocean side of our garden, washed once to remove any salt. We have tried bagged top soil, a ceramic aquatic medium, cat litter, a local sand/clay mix, additives such as PondTabb pieces or crumbs, granular fertilizer, bone meal and SuperThrive sometimes mixed with our sand and in every possible combination. Only the strongest seedlings did not disintegrate almost immediately.
The critical ingredient for success is the addition of one tablespoon of good quality peat at the bottom of the cups. We thank Craig Presnell for this breakthrough that has improved our survival rate from, at best, one in 20 to as high as 19 of 20. Our Initial Experiments With Peat & Peat Works