Dealing with phosphates (again?)

[RoachF4]

Hey all...just looking for some feedback, suggestions, and/or opinions. My 180 has seen a steady increase in algae/phosphates over the last couple of months and I've really been too busy to investigate the problem. Finally tested the freshly made salt water (in the barrel) and the fresh water (separate barrel). The newly mixed salt water, using Reef Crystals forever now, came up with .14 per Hanna Colorimeter and the RO/DI water came up with .04.
I just changed the filters on the RO/DI unit about a month ago, RO membrane is about 4 years old, but still putting out only 2 tds before the dual resin chambers (0 after that per inline meter and handheld).
I guess I have two questions:
1) Could the Reef Crystals really be adding .1 ppm of phosphates to the water as the test would indicate?
2) Is my RO membrane ready for replacement, even with the low tds and how come the DI resin isn't picking out the PO4? OK that was 3.

Thanks for your time.

Roach

[bertoni]

Which colorimeter do you have? The Phosphorus ULR is rated only for saltwater. What was the TDS right after the DI cartridge was replaced? The DI should be replaced as soon as the TDS starts to rise.

There have been some bad batches of reagents for the Hanna phosphate meters. You might want to check in their forum about the ones you're using, although your meter is giving much more credible numbers than some.

I hope that the Reef Crystals doesn't have that much phosphate in it. It shouldn't, and normal batches don't.

[RoachF4]

Bertoni,

It's the Hl 713. Reagents are Hl 713-25. Lot # H046. Expires 11/2015.
I remember awhile back that they had problems with the checkers themselves...I actually sold my first one because of the mixed results. I bought another one a few months back and it seems to be a little more consistent.
As for the RO/DI unit, I may have been a little unclear in my first post. The water coming out after the DI resin has always been 0. Water going into the DI resin is 1-2 tds. I have two DI cartridges so I always replace one before the other turns completely brown.

[bertoni]

Okay, that one is good for fresh water, too. I might try mixing up a fresh batch of RC in a recently-cleaned container of some sort, and measure the phosphate right away. If the container you got is that bad, I might try to get a refund.

What does the tank measure for phosphate?

That sounds like good maintenance practice for the RO/DI. I should have read more closely.

[RoachF4]

I plan on mixing up some RC in a clean bucket and testing it out as soon as I get home. For the past two years I've been using some "used" 50 gallon food grade drums for both RO/DI and new salt water. The drums had been used previously for holding olives. They had a little bit of gunk in them, but I cleaned with RO/DI water + vinegar and left them in the hot NorCal sun for a day. I was worried at the time so I tested quite a bit in the beginning and never came back with phosphates or anything else out of those two drums. Who knows...maybe something is breaking down. Thanks for the advice Bertoni.

Roach

[bertoni]

You're welcome! Good luck!