[APD] Suggestions on lights or RODI

["Steve" <steve_wilsonii at fishpalace_org>]

I have a 75 gallon tank with 2 175 watt metal halide pendants that has been set up for 9 months. It has Flourite/Onyx substrate with about 2 cups of peat mixed in the lower layer. I was dosing with PMDD, then Flourish and Flourish Trace, and now I am back to PMDD. My Tank has been very sensative to any changes, and even trimming my stand of bacopa has helped to kick off a plague hair algae or BGA. Some further tank stats are PH 6.6, 4ºKH, 2ºGH, pressurized CO2, Eheim Pro 2224, and an assortment of plants. I have tried dosing with Tom Barr's method and I was not very successful, because I kept loosing track of when to dose. I went back to dosing daily, so that way I do not forget. Now on to my delema...

My tap water contains .52 mg/l of Zinc, 3.6 mg/l phosphate, 25.3 mg/l sodium, 9 mg/l sulfate, and 40 mg/l chloride. The other minerals are not very high, but still I have to pre-filter the tap water through carbon and a phosphate reducing resin before adding it to my tank. When I change 10 gallons and I filter, then I am usually good to go, but if I have to change out 20 gallons, I am sure to get an outbreak of BGA. 

I am under the impression that using reverse osmosis water will help me to keep a good balance, and avoid some of the guess work. On the other hand I could also switch the lights out for compact flourescents and not have such a sensative system. I have been able to keep the tank teetering on the line between luxuriant growth, and hair algae or bga outbreak. I was able to keep one of my metal halide pendants on my 29 gallon tank for about 5 months before I got a larger tank. The 29g had compact florescent lighting and was growing not half bad, but once the MH pendant was installed, the growth exploded and the tank was so thick with growth, and I REALLY want to duplicate this. 

Can someone share some of their experiences or knowledge with me regarding what would be better. I have the option of either getting an RO unit or Compact Flourescent lighting for christmas and although I would rather keep my MH lighting, I want to make the most informed decission. I was also considering getting a good test kit, but I have all the Hagen test kits for fresh water and they seem to work OK and match the city's water tests, with exception of PO4 which varies daily between 2-4 mg/l. What do you think?

Thank you
Steve
_______________________________________________
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com
http://www.actwin.com/mailman/listinfo.cgi/aquatic-plants