Re: Elevated Phosphates

From: rnisd0::mrgate::"a1::maladord"@2.6.ENET.my.domain

> The substrate is gravel, with a lower layer containing some laterite,
> peat and Delaware Imports tablets.

I would suggest you stop using the Delaware Aquatics tablets.  At one
time they were known to contain nitrates and phosphates. 

> Most plants grow, but in a stunted manner.

You didn't mention if you used other fertilizers.  I doubt if DA
tablets are complete enough.  The suspicion is that they are simply
houseplant fertilizer.

> 2) I bought several pouches of Phos-Zorb, which I am using one at a time,
> replacing it when phosphate levels stop dropping. 

Some types chemical filtration are non-specific, i.e., they remove
other trace elements as well.  I don't konw about Phos-Zorb
specifically, but PolyFilter removes all kinds of good stuff. 

> 3) What levels [of phosphate] should I realistically try to achieve?

Less than 0.1 mg/l.

George Booth