Low range phosphate from rodi and tank test

[Fishie]

I have a Hanna low range phosphate calorimeter and tested my dt and rodi water

The rodi reading was 0.09 on the screen so times .33 being 0.0297 of phosphates

 

At the dt it was .12 so times .33 being .0396

 

An acceptable phosphate is 0.03 so I am about 0.01 above...

 

Is this all correct or am I readin things wrong

 

Also if it's right...any suggestions on bring it down further ...I use chaeto and gfo reactor ...I change the media once every 2-3 months...

[Origami]

Do you have the low range PHOSPHATE (HI713) or the low range PHOSPHORUS (HI736)? If the HI713, that unit reads directly in PPM (parts per million) according to the manual. The HI736 is an ultra-low phosphorus colorimeter that reads phosphorus in ppb (parts per billion) and you use a conversion factor for that model to convert to ppm Phosphate.

 

Phosphorus is an element. The symbol is P. It weighs about 31 amu.

 

Phosphate is an ionic complex. It's formula is PO4---. It weighs about 95 amu.

[Origami]

If interested, here's something I wrote a while back about the two meters:

http://www.wamas.org/forums/topic/44662-hanna-checkers-gauging-interest/page__view__findpost__p__375681

[Fishie]

I have the hi 93713...different from the above link

 

http://www.hannainst.com/manuals/manHI_93713.pdf

 

So should I be using the screen number or do I need to multiply by 0.33

Edited August 4, 2012 by Fishie

[Origami]

I have the hi 93713...different from the above link

 

http://www.hannainst.com/manuals/manHI_93713.pdf

 

So should I be using the screen number or do I need to multiply by 0.33

I just looked at the manual. It's has the same range and reads exactly like the HI713. It reads phosphate (PO4---) out directly in PPM. When you multiply by 0.33 (which is the ratio of phosphorus to the total phosphate ion weight, 31/95), you get the Phosphorus content of the water in ppm. The metric that we usually gauge by is Phosphate, that is, PO4---.

 

The manual is somewhat confusing to users because it has this line in it: "To convert the PO4 3– ion concentration to Phosphate P concentration, multiply the reading by a factor of 0.33." What they mean to say was, "To convert the PO4 3– ion concentration to Phosphorus P concentration, multiply the reading by a factor of 0.33." Again, phosphate is PO4 and Phosphorus is P.

 

This means that your phosphate levels are 3x higher than the estimates in your first post since you effectively divided them by 3.

 

The phosphate out of your RO/DI system is extremely high. Using it as a top off source only concentrates it in your display tank. I suspect that your DI resin is exhausted. Did you take your RO/DI sample directly from the unit or from a storage container? Take it directly from the unit after letting it flow for a minute or so. Also, if you can, take a tds reading (with a tds meter) of your source water (going into the RO/DI unit) and again directly after your RO membrane stage, but before your DI resin stage. This will give you some idea of of the performance of the RO membrane (which can become less effective over time). If the membrane is letting a lot through, then the DI resin exhausts more quickly making it expensive to operate.

[Fishie]

Oh boy...3 times more...so I checked few things

 

The tds is 1 or 2 from the rodi final output

Tap water is about 170

The ro only tds is 6

 

Here is what i think my problem maybe...the membrane I have been using is the filmtec 100gpd tw30-1812-100

 

After doing some more readin that is the worst membrane to be using for reefkeepers

I used to have a 75 ...which was fine but I went and got a 100 to increase production thinking that they all function the same inside ...lol ...not the same rejection rate

 

So I've put back my old 75 in now...did a fast flush and I am draining some ro water to test again in a bit

 

The Di resin is still blue for the most part...only the bottom section is brown about a couple inches of it

 

I also plan to replace the ore filter medias...I don't think mine have been updated In about a year now...so I'll change the 2 carbons and go with the 5 micron sediment filter from brs...another qck question...are the brs filters compatible with awi rodi units like the typhoon

Edited August 4, 2012 by Fishie

[Origami]

The 100 gpd membrane is definitely part of it. It's rejection rate is poor. 96.5% from your readings. Also, if you didn't change your flow restrictor, it may not be running well.

 

It's still possible that part of your DI resin is exhausted. Remember, it's a mixed bed resin that's a combination of an anion and a cation resin. Two types. If one is exhausted, it won't do it's job right. For example, if the anion resin depleted, phosphate will get through. I don't know if the colored indicator that they use in these mixed bed resins are only on one of the resin types.

 

Continue to monitor your RO/DI output. If the DI resin is doing it's job, the TDS should read zero.

[Origami]

How long have you been using the 100gpd membrane? And how long did your DI resin used to last when on the 75 gpd membrane?

[Fishie]

Ok thanks much...if I don't see a positive change I am just planning to replace all 3 filters a new resin and a new membrane

I took my old membrane out of retirement...I put it into retirement for the wrong reason to begin with 100> 75 ...silly me

[Fishie]

How long have you been using the 100gpd membrane? And how long did your DI resin used to last when on the 75 gpd membrane?

 

 

100 gpd about a year now...and I was also ignorant about the do resin for the longest time when using the 75...so I didn't change it until my tds started jumping up...and I called awi and said what was going on and ended up getting a new membrane and new carbon and sediment filters...

I don't think my do was changed even then...

 

My most recent di change was 3 months ago to the nuclear grade version from brs

[Fishie]

Been 10 minutes still no water coming out

[Origami]

I think that your old membrane dried out. If it wasn't kept moist, it'll dry out and is pretty much trash. I think that I saw a membrane at BRK the other day. Give them or Fins and Feathers a call. They may have one on the shelf.

[Origami]

My most recent di change was 3 months ago to the nuclear grade version from brs

With that membrane, you'll burn off resin at a 2 to 5 times faster clip.

[Fishie]

I think that your old membrane dried out. If it wasn't kept moist, it'll dry out and is pretty much trash. I think that I saw a membrane at BRK the other day. Give them or Fins and Feathers a call. They may have one on the shelf.

Dried out..so it's trash at this point right?

F&f has the 100

 

I'll just use my 100 until the new 75 from brs comes in..

[Origami]

Yes. It's pretty much trash if it's dried out and water won't flow. You might be able to use it to play fetch with Rover....

[Fishie]

Rover aka echo likes his new toy

 

Ordered up a filter pack, resin and new 75 gpd membrane

Also got a new phosban reactor...I didn't like the old one.. it wasn't tumbling the way I'd like...

 

 

I will retest when everything comes in and post results..

Edited August 4, 2012 by Fishie