Elodea+Growing+Race

Compete to grow the most elodea in a fixed amount of time. http://fins.actwin.com/aquatic-plants/month.9702/msg00228.html

Elodea will send down roots on its own so you can just float it in a tank. I'd put a layer of ordinary black garden soil in the bottom of your tank and cover this with a layer of clean sand. Don't use soil or sand you collect from near natural water bodies to avoid introducing nasty types of algae. The soil will provide most of the micro-nutrients you require for growth. It is a good idea to include daphnia and snails in the tank especially if it's going to get direct sunlight.

When you purchase your Elodea, inspect it carefully to make sure no green hair or filament algae gets into your tank.

If you have very soft water, you could add 1 tsp of CaCO3/10 gal to your water to increase the calcium content. It would also be good to add potassium and magnesium. You could use the following from the PMDD dosing method:

In 300 ml of distilled water dissolve 2 tsp K2SO4 (potassium sulfate) and 3 tbsp MgSO4.7H2O (fully hydrated magnesium sulfate, aka epsom salts) If you dissolve CO2 in the water, you might need about 1ml of this per day or 5ml per week. If you're going to add nutrients like this for which there are no simple concentration tests, you should change about half of the water in the tank with cold tap water every month.

The soil will provide some initial amounts of nitrogen and phosphates, perhaps enough to create a green water algal bloom. That's what the daphnia are for. To get faster growth, you can add an ammonium fertilizer to get 1-5 ppm ammonia. You will need very little. Ammonia test kits are cheap and readily available in aquarium and pet stores. I'm assuming there are NO FISH in your tank. If there are, the fish will supply all of the ammonium you need. Addition of more could be harmful or lethal to the fish.

The plants will grow much faster if you have a CO2 source in the tank. Organic soil (no more than 5% organic) will provide some CO2 or you can use the yeast method to generate CO2. See krib archives. If your pH is rising, your Elodea is using CO2 from carbonate and you need to dissolve CO2 in the water (or add more carbonate, and change more water).

The temperature for Elodea is not critical. It will grow in temps from 60F to 80F for the species available in the aquarium trade.

Don't use any kind of filtration such as biological filtration as for fish aquariums. This will cause the useful ammonia to be converted to nitrate with an accompanying reduction in pH. Plants MUCH prefer ammonia as a nitrogen source.

Good luck! Elodea are excellent plants for growing with fish to keep the water conditioned and oxygenated.

Steve Pushak spush at hcsd_hac.com Vancouver BC Canada