phosphate removal via skimming?

polywise

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I have been in this hobby for quite a while, and seem to be having a bout of
sometimeheimers

Does a protein skimmer help remove phosphate? Can it be used as a only method? or does it have to be removed with a media like phosban, filterpads, or water changes?

I currently do weekly water changes which = 30% WC / month
run RODI & change DI resin when reading goes up to 3
my phospates have been bouncing around between
Hanna 0.04 to 0.01

feedback would be appreciated
 

lnevo

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I personally would change DI at one or above. Your phosphates look fine though. A skimmer will help by removing some organic matter but will not remove phosphates directly. I currently change about 20% a week but that's pretty excessive. Need to start scaling that back a bit.
 

Boomer

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Skimmers will remove organic phosphate directly as will GAC, due to hydrophobic adsorption. As far a orthophosphate, which is the only phosphate we test, it will be about nil, not worthy of a mention. A skimmer could be dedicated to remove orthophosphate throughout co-precip with Calcium, were Kalk is cycled through a skimmer. The real issue here is the constant cleaning of the skimmer and all the precip that often sticks to the skimmer walls.


Poly

You have have high CO2 in your house water supply. What is the pH, TDS, temp and Alk of the water after the RO but before the DI ? From this one can calculate how much of the DI is depleted by CO2. We have made calculators for this.
 

Boomer

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That 4 ppm before the DI may be a good number. That 2 ppm after DI is not good, time replace the DI resin. DI should be changed ~ 1-2 ppm TDS. Just for the sake of it, what is the TDS of the tap water city/well line ? In general, a good properly running RO will leave behind 2-4 % of the tap TDS. A really crappy / cheap RO units can be 2 x that, like 10 %. And very high quality RO 1-2 %.


So, if you had say 250 ppm TDS vs 100 ppm TDS tap water.

250 ppm TDS x 4 % = 10 ppm TDS max

100 ppm TDS x 4% = 4 ppm TDS max
 

BKLYNREEF123

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Is it uncommon to get 0 TDS after RO only? I am running a 5stage BRS RODI system and was questioning the meter. I have not changed the position of the meter to check readings before the RO
 

Boomer

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Yes, it is uncommon but one can get it. For example, the tap TDS is 100 ppm and the RO is a good unit giving 99 %. 100 x 1 % = 1 ppm. These meters have what is called a Accuracy rating. Almost all of them are no lower/ better than +/- 1 ppm. That means if the meter reads say 7 ppm the actual TDS is guaranteed to be somewhere from 6-8 ppm.

Take the probe out and air dry it and see if it reads zero.
 

ohana888

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Skimmers will remove organic phosphate directly as will GAC, due to hydrophobic adsorption. As far a orthophosphate, which is the only phosphate we test, it will be about nil, not worthy of a mention. A skimmer could be dedicated to remove orthophosphate throughout co-precip with Calcium, were Kalk is cycled through a skimmer. The real issue here is the constant cleaning of the skimmer and all the precip that often sticks to the skimmer walls.


Poly

You have have high CO2 in your house water supply. What is the pH, TDS, temp and Alk of the water after the RO but before the DI ? From this one can calculate how much of the DI is depleted by CO2. We have made calculators for this.
hi boomer,

is this correct: skimmer removes organic P & macros remove inorganic P?

thanks!
 
M

Moneymaks24

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One way of removing phosphates via skimmer is:
adding phytoplankton additives, shutting skimmer off for 20 min, allow phytoplankton to ( absorb/eat phosphates ) then turn skimmer back on to remove the phytoplankton and phosphates together.

( read this not sure if it works however)
 

Boomer

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Yes Doug, pretty much correct. However, Cyanobacteria can also remove organic P and inorganic P. Using Kalk will also pull out some inorganic P.
 

ohana888

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Yes Doug, pretty much correct. However, Cyanobacteria can also remove organic P and inorganic P. Using Kalk will also pull out some inorganic P.
does kalk & p become inert? can i dose the kalk into a sock like i would lanthanum chloride to catch the inorganic P? thanks!
 

Boomer

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The Kalk causes the production of Calcium phosphate due to the high pH of the Kalk. Yes, you could trap it in a sock like Lanthanum. How well that would work I do not know.
 

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