Why don't you just get an RO/DI unit off of ebay for less than $100 shipped like I did and be done with the naitrate problems. Mine hooks to the faucet and I fill my jugs when needed. I've been running this unit since starting this tank and have yetr to get any algae problems.  
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20gl cube
168wt 50/50 PC
1x 1200 MJ PH
approx. 25# LS
34# Fiji LR
various mushrooms, rics, zoos
1 Cherub angel
2 yellow watchman
1 Tiger pistol
1 Astrea snail
5gl AGA fuge
chaeto |