Join Date: Apr 2013
Location: Skinners Mudhole
Oh wow! That is rough. I'm guessing others will come along and suggest RO water. Cuz if there is that much nitrate in your tap, well, I'm not sure if there is anything you can do about that.
On duckweed...see if you can find the "greater duckweed". It is larger leaves and so therefore much easier to control if you ever want to get rid of it than the little tiny duckweed. I just received an order of asian watermoss, aka salvinia cucullata. It has short little roots and my shrimp are all over it ever since they realized it was there. If it is at all of interest to you, PM me cuz even though I just got it, I have enough I'm sure I could part with a bit that would get you started. I'm guessing it will multiply like crazy and in a few weeks I'll have too much as it is. I'm having a nitrite issue, so I feel your pain.
I hope someone is able to help you find a reasonable solution.