[Delphinus]

Beggars can't be choosers .. I'll come find you.

Sounds like we have the same unit ... I'm really disappointed that I'm getting such inconsistent results with it so I don't know what's going on, either I've got PO4 worse than I ever imagined or the thing is just faulty (wouldn't be the first time, I had to send my nitrate meter back because it wasn't working right), or I'm doing something wrong.

For example, get a load of these results:
- Tank 1: PO4 = 0.10 (this is the tank that can't keep SPS alive no matter what). Topoff is RO/DI.
- Tank 2: PO4 = 0.08 (this is the nitrate disaster tank). Topoff is tap water.
- Tank 1 Phosban reactor effluent: PO4 = 0.11 (higher than the tank water??)
- My tap water: PO4=0.05
- My FW tank: PO4=0.13 (tap water)
- My RO/DI: PO4 = 0.23

The thing that has me absolutely stymied is the reading of 0.23 of my RO/DI. The TDS of the RO/DI output is zero so I was under the impression that it was working fine. Having wrecked several membranes I've now learned to keep a close eye on the TDS just to be sure I'm not wrecking this one. But to have input=0.05 and output=0.23 ?? Now I'm just suspicious of everything. Granted I tested the water that sits in my reservoir and not fresh output, but 1) the water is no older than a couple days and 2) where would the PO4 even be coming from?

I'm so confused. I don't talk much about my lack of SPS these days on the board but I find it completely demoralizing to know that I've had to give away (or watch die) every acropora, every montipora, in short every SPS I've ever had (some that I've had for years and years), because that they just don't live. They grow a little, then boom, half will succumb to RTN or STN. Then they grow a little more, then boom, another half will succumb. Eventually the math catches up to them and there's nothing left. I *thought* it was a phosphate issue because I don't see what else it could be.

Ahhhhh I digress. The point is, I don't understand why the readings are so over the map. Once I can get zero readings for PO4 on my tanks (and have confidence in the readings), if I still can't keep SPS after that, that will be a bridge I jump off another day. For now, the immediate goal is to figure this PO4 crap out.