Help with planted tank

[Shazor]

ok I have a 20 gallon planted tank which has been setup for about 6 weeks now. I do 25% water changes once per week.

30 Watts Flourescent Lighting (1.5wpg)
PH 6.8
KH 50 mg/l
GH 30 mg/l
NO3 10 mg/l
PO4 5 mg/l

Basically all the water I have used on this tank has been R/O. I leave the light on 12 hours a day. The substrate is 3 lbs Laterite, 15 lbs Onyx Sand, 5 lbs black gravel. I have not added any substrate fertilizer. Once per week I add 5 ml of Hagen Plant Gro. I also have the hagen CO2 reactor on the tank.

There are 2 black molly's, 2 platies, 1 otocinclinous, 1 blue ram and 2 ghost shrimp in the tank.

Plants are 2 Amazon Sword, 4 Small Sword Plant(Covered in algae), 1 Red Temple Plant bunch, 2 bunches of water wisteria, 10 or so bunches of Filigree Foxtail, and one clump of java moss (These are the names I was given when I purchased the plants not sure if they are correct).

The foxtail plant seems to be growing like crazy. It literally grows about 1/2 inch a day. The large sword plants seem to be doing fine so far. The small sword plants are covered in some sort of brown algae that I cannot rub off with my finger. None of the other plants have any visible signs of algae so far.

From reading these forums my water measurements sound wacky. Is my phosphate way too high? I'm using a hagen test kit and 5.0 mg/l was the max for the test scale. What exactly would cause high phosphate levels and how would I correct that. Also is my KH and GH too low? Could anyone please give me tips on what I should do.

Thanks

[MrGoodbytes]

I wish I had water as soft as yours.

You phosphates are waaay too high. The should be closer to 1ppm for a better balance. They could be coming from too much food, if you are overfeeding. Are you adding any phosphate-based buffers or supplements after you run the water through the RO filter?

If you feel your water is too soft (if you want to add CO2, for example), then add a small amount of calcium carbonate (coral gravel, limestone).

Graeme

[Dwarfnut]

JMO, but I think you need some more light. The 20 gal tank is pretty tall relative to it's size, so it is harder for the light to get towards the bottom. Also, what type of light bulb are you using?

Sounds like you are maybe over-feeding both the fish and plants and they are not able to use up the fertilizer. If you had more light, they would use it faster, or cut back to like every other week.

Best of luck,

[Shazor]

I have two 20 inch strip lights that have 15 watt flourescent coralife daylight bulbs. I agree I need more light but its just an expensive upgrade. Ideally I would like to use the coralife aqualight 24 inch strip. It has 65 watts of compact flourescent which should be more than enough light.

I have stopped using the r/o water. I found out that the station I buy it from somehow adds phosphate to the water as it has 5 mg/l straight out of their tap. I'm going to just use tap water and a python no spill to change water. For comparison my tap water has barely any phosphate when I test. I've just refrained from using tap as it tends to be around PH 9.0.