PO4 in RODI

[Travis Stewart]

So I've been trying to solve a repetitive PO4 problem. I finally tested my RODI water and found .09 PO4. What do you do with that? TDS is reading 0

 

[Travis Stewart]

Bump

 

[jsker]

That is a hard one, In the last week I have been researching my issue with burning through Di resin. I would suggest a prefilter with a phosphate removal media. here is some information on phosphates used in drinking water process link what is your reading in your system? It is good to have between a trace to .02 in ULNS and .02 to .04 in higher nutrient systems.

 

[Travis Stewart]

I just started running a GFO Reactor recently and it is helping. Not sure I'm down to .02-.04 yet. I did take it from .18 to .07 in first week so going in right direction. Worried because if I do a water change I'm increasing my PO4 which doesn't make sense...

 

[jsker]

Lanthanum Chloride link I have used on of the product to bring down my phosphates and still do that are on the search page. As far as going into the filter, there are product out there that you can setup another chamber for your Ro/DI unit to pull the phosphates out. Mine is Chloramines/ammonia. I am adding a new single chamber and then adding a double carbon filters.

It is like we need to prefilter the water and filter it again

 

[Travis Stewart]

Lanthanum Chloride link I have used on of the product to bring down my phosphates and still do that are on the search page. As far as going into the filter, there are product out there that you can setup another chamber for your Ro/DI unit to pull the phosphates out. Mine is Chloramines/ammonia. I am adding a new single chamber and then adding a double carbon filters.

It is like we need to prefilter the water and filter it again

Sounds stupid to me. I don't know about doing all that...

 

[Travis Stewart]

Do you know how much work it took me to get to 0 TDS and now this lol

 

[jsker]

Sounds stupid to me. I don't know about doing all that...

It's a learn process, and you have a good resource here at R2R for knowledge. There is no stupid question, except the one that was not asked

Do you know how much work it took me to get to 0 TDS and now this lol

Look at your TDS before it goes in to the RO membrane, that will give you a good answer of how much your DI is working. I am at 10 or 11 right now, I need to get it down to 2. What size sediment membrane are you running? I am running a one micron sediment filter. I am finding after the sediment filter it is what type of carbon that is run. I am finding out that the more carbon and type of carbon, before the water hits the membrane the DI make a big difference.

Like yourself I have battled phosphates and the lanthanum chloride really helped me export the phosphates. In a 80 gallon water volume I now run a quarter cup of GFO to keep my phosphates in line in in the system. I change the GFO about every two weeks and when I see the phosphate starting to spike, I treat the system with a phosphate remover. One other thing to look at is how much algae is in your system. If you have a bunch algae, the nutrient readings run false because the algae is using the nutrients to grown. It depends on the system for the reason each system is different, but running higher nutrients is not a bad thing if your tank look good. Besides balancing the parameters in a system there is also balancing the phosphates and nitrates.

 

[Travis Stewart]

I amber currently pumping 5 TDS in before it hits DI. I tested salt water after mixing it and it went down. I think I may have been getting an inaccurate reading.

 

[saltyfilmfolks]

How are you sampling the water. From the bucket or a clean sample like from a clean glass.

 

[Travis Stewart]

How are you sampling the water. From the bucket or a clean sample like from a clean glass.

Straight from the RODI unit

 

[saltyfilmfolks]

Straight from the RODI unit

hmmm....
http://www.reefcentral.com/forums/showthread.php?t=2318622

 

[skim]

What did you use to test for Phosphate. If you used Hanna Phosphorus test, it will give an inaccurate result as it is made for Marine use and I believe the reagent is designed for saltwater use. RO should remove 90% + of any Phosphate in your water and the DI resin removes the rest. Your Phosphate problem is more than likely from Food, all that needs to happen once is your phosphate be high and it will become absorbed into your rock and substrate and then it becomes a source as it slowly releases it into the water column. Your best bet is to A. not bother with it as long as you have no Algae problem or B. be more consistent and aggressive with the use of GFO. If you have no Algae problem and are just chasing numbers I would not worry about it as you can end up causing more trouble than it's worth.

 

[Travis Stewart]

I had .18 in my water column. Yes using hanna. After the start of GFO, I have it down to .06 as of now..

 

[Randy Holmes-Farley]

So I've been trying to solve a repetitive PO4 problem. I finally tested my RODI water and found .09 PO4. What do you do with that? TDS is reading 0

Nothing special (IMO) is likely required. It isn't the cause of elevated phosphate in the tank (at least, not the primary cause).

I address that here:

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both
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.

The same sort of calculation applies to analyzing other phosphate issues, such as the GAC in scenario three. The issue of finding "high" phosphate in GAC soaked in fresh water was frequently quoted as a reason to use one or the other brand of GAC, and probably still is. But simple analysis as shown above for the food rinsing puts the lie to this being a big problem.

One needs to consider how much GAC one will really use in the aquarium and how often it is added in order to interpret how important the added phosphate is. A typical recommendation might be 1 cup of GAC per 100 gallons of aquarium water, and to change it in 4-6 weeks. Let's assume we detect 0.5 ppm phosphate when a teaspoon is placed in a cup of water, and we get scared by the dark blue color during the test. Is this reasonable? That 0.5 ppm from a teaspoon in a cup of water translates to 0.015 ppm phosphate when a cup is used in 100 gallons.

That 0.015 ppm may be significant, being a typical target concentration level for reef aquaria and amounting to about half to a twentieth of the amount added daily in foods, but remember, it is used for 4-6 weeks. During those 4-6 weeks before the next replacement, foods add 50-700 times as much phosphate. So while it is not unreasonable to look for another brand of GAC, to blame phosphate or algae issues in the aquarium on its use would stretch credibility because it is a very tiny portion of the total phosphate being added.

 

[Travis Stewart]

Nothing special (IMO) is likely required. It isn't the cause of elevated phosphate in the tank (at least, not the primary cause).

I address that here:

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both
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.

The same sort of calculation applies to analyzing other phosphate issues, such as the GAC in scenario three. The issue of finding "high" phosphate in GAC soaked in fresh water was frequently quoted as a reason to use one or the other brand of GAC, and probably still is. But simple analysis as shown above for the food rinsing puts the lie to this being a big problem.

One needs to consider how much GAC one will really use in the aquarium and how often it is added in order to interpret how important the added phosphate is. A typical recommendation might be 1 cup of GAC per 100 gallons of aquarium water, and to change it in 4-6 weeks. Let's assume we detect 0.5 ppm phosphate when a teaspoon is placed in a cup of water, and we get scared by the dark blue color during the test. Is this reasonable? That 0.5 ppm from a teaspoon in a cup of water translates to 0.015 ppm phosphate when a cup is used in 100 gallons.

That 0.015 ppm may be significant, being a typical target concentration level for reef aquaria and amounting to about half to a twentieth of the amount added daily in foods, but remember, it is used for 4-6 weeks. During those 4-6 weeks before the next replacement, foods add 50-700 times as much phosphate. So while it is not unreasonable to look for another brand of GAC, to blame phosphate or algae issues in the aquarium on its use would stretch credibility because it is a very tiny portion of the total phosphate being added.

What if I'm only feed every other or every third day..

 

[Randy Holmes-Farley]

What if I'm only feed every other or every third day..

Then maybe the food accounts for 10 times the RO/DI input and not 100 times. lol

In any case, it is fine to try to reduce the phosphate in the RO/DI (second DI cartridge, GFO in the RO/DI effluent, etc.), but my point is, it is not the major problem it seems to be (even if it is accurately measured) at the level your report.