rodi storage container leaching po4

711reefer · Dec 1, 2016

I have been having a po4 problem in my reef for a while now. I have been using large amounts of gfo and phosguard to help lower po4. I have even resulted to using some lanthalum chloride as well. I decided to check my rodi unit and it measures 0 coming straight from the tap. I then checked my rodi storage container and it measured 20 on my hanna ulr checker. I decided to empty it and fill with fresh rodi and it measured 0 once filled. 4 days later it is measuring 11 now. it seems as though my storage container is leaching po4. I bought it from a place that says its for water storage. the bottom says hdpe 2 on the bottom. I am baffled on how it could be leaching po4. do you have another recommendation for rodi water storage ? attached is a pic of what I am using

skim · Dec 1, 2016

You can not use the the Hanna checker to test Fresh water/RO water as the reagent is designed for Salt water. You will get in proper readings. That straight from Hanna. Your Phos. is most likely coming from the food and your rock work and substrate may have absorb some and slowly releasing back into the system.

Randy Holmes-Farley · Dec 1, 2016

Even assuming it is accurate, if you mean 20 ppb phosphorus, that is an insignificantly small amount and is not the cause of any problems.

I address that issue here:

http://www.advancedaquarist.com/2012/3/chemistry

from it:

Comparison of Food Sources of Phosphate to Other Sources
What about other sources of phosphate, like the "crappy" RO/DI water containing 0.05 ppm phosphate? A similar analysis will show it equally unimportant relative to foods.

Let's assume that the aquarist in question adds 1% of the total tank volume each day with RO/DI to replace evaporation. Simple math shows that the 0.05 ppm in the RO/DI becomes 0.0005 ppm added each day to the phosphate concentration in the aquarium. That dilution step is critical, taking a scary number like 0.05 ppm down to an almost meaningless 0.0005 ppm daily addition. Since that 0.0005 ppm is 40-600 times lower than the amount added each day in foods (Table 4), it does not seem worthy of the angst many aquarists put on such measurements. That said, tap water could have as much as 5 ppm phosphate, and that value could then become a dominating source of phosphate and would be quite problematic. Purifying tap water is important for this and many other reasons.