High Phosphates - New Pico Reef

[Yahtzee170]

I recently started a pico reef tank ~2 gallons in a cookie jar. I added BIO-spira and dosed with Fritz ammonium chloride for the cycle. I continued until the tank was able to convert ~1-2 ppm ammonia into nitrate within 24 hours. I did a 90% water change to remove the nitrates, and tested the tank a day later:

34.8 PPT
78.0 temp
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate 1 ppm
Phosphorus > 200 ppb (> 0.613 ppm phosphate)
Calcium 421 ppm
Alkalinity 8.6 dKH

I'm confused on where this phosphorus is coming from. I'm using Tropic Marin Pro-Reef salt (freshly mixed at 35.9 PPT gave 8.8 dKH, 436 Ca, and 24 ppb phosphorus), and about 2 pounds of formerly live rock that was cured in RODI water. RODI water remains at 0 TDS. Any ideas? Other than the phosphorus am I ready to add a few coral?

 

[Mike N]

I recently started a pico reef tank ~2 gallons in a cookie jar. I added BIO-spira and dosed with Fritz ammonium chloride for the cycle. I continued until the tank was able to convert ~1-2 ppm ammonia into nitrate within 24 hours. I did a 90% water change to remove the nitrates, and tested the tank a day later:

34.8 PPT
78.0 temp
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate 1 ppm
Phosphorus > 200 ppb (> 0.613 ppm phosphate)
Calcium 421 ppm
Alkalinity 8.6 dKH

I'm confused on where this phosphorus is coming from. I'm using Tropic Marin Pro-Reef salt (freshly mixed at 35.9 PPT gave 8.8 dKH, 436 Ca, and 24 ppb phosphorus), and about 2 pounds of formerly live rock that was cured in RODI water. RODI water remains at 0 TDS. Any ideas? Other than the phosphorus am I ready to add a few coral?

I think you're seeing freshwater bacteria die-off.
Proper curing of dry rock is done in salt water

Here's a thread on the very issue from a couple years ago with some more detailed explanation:

Curing dry rock in RO/RODI vs SW

I have a lot of dry rock to cure. I would prefer to cure in RODI water to save some cash on salt. Any advantages to curing in saltwater vs RODI?

www.reef2reef.com

 

[Yahtzee170]

I think you're seeing freshwater bacteria die-off.
Proper curing of dry rock is done in salt water

Here's a thread on the very issue from a couple years ago with some more detailed explanation:

Curing dry rock in RO/RODI vs SW

I have a lot of dry rock to cure. I would prefer to cure in RODI water to save some cash on salt. Any advantages to curing in saltwater vs RODI?

www.reef2reef.com

Interesting. If I'm understanding that correctly, then my tank has cycled but the rock hasn't cured yet? It has been in salt water for 3 weeks, although I've only completed 1 water change in that time.

 

[Mike N]

Interesting. If I'm understanding that correctly, then my tank has cycled but the rock hasn't cured yet? It has been in salt water for 3 weeks, although I've only completed 1 water change in that time.

Yes, that is correct.
Anytime you take rock from freshwater and add it to salt (or vice-versa), there ill be die-off from bacteria and your curing process starts over.

 

[LesPoissons]

+1 I would give it more time and let the rock cure. Other considerations: are you storing water in anything non food grade? I've seen people use storage containers like rubbermaids that leech phos like crazy.

 

[Yahtzee170]

I’m using Seachem 2.5 gallon containers. The freshly mixed saltwater was low in phosphates before it went in the tank, so I agree the rocks are the source. Thanks!