reducing phosphates

[MsBeanCtr]

Originally Posted by lando

I agree .8 is high. You can use your regular SW test kit in your RO/DI water. I also suggest getting a test kit from a different company to verify your results.

The two most common causes of PO4 in a tank are source water and food. IMHO, food is a major contributor to PO4, especially if you use frozen food. Can you explain what you feed, how often and how you prepare it?

I alternate between seaweed and several different foods. For example...one day is seaweed, the next day is a cube of frozen food (mysis, emerald entree, or "Rod's" food, which is a commercial frozen food--a blended mixture of clams, squid etc.) , skip a day then a pinch of prime reef 1 or 2. I always make sure I thaw the frozen and squeeze out the excess liquid (as I understand that's loaded with phosphates). The only other thing I can think of is that I also feed my sun corals 2 times a week but I use a feeding bell. I feed them a mixture of mysis shrimp and DT's (the green stinky stuff).

So, I'd say they get fed 2 days then off for a day.....and repeat.

I'm just doing another batch of ro/di water tonight so I'll test it again with a different kit.

Depending on how my tests come out....I might seriously consider installing a phosphate reactor in my sump (or on it). Does anyone have a picture of their installation?

Oh! And thanks very much for the help folks. This is honestly driving me nuts.

[lando]

I would thaw and rinse (several times) any frozen food you add to the tank with RO/DI water. Simply thawing and sraining will not be enough. Also, try cutting back on the DT's. It is more benefical for filter feeders, which your sun coral is not. It can also contribute to PO4.

[Kurt_Nelson]

What about your seaweed? Are you using grocery store nori or seaweed from the LFS? I don't feed nori, but am wondering if that might not be a source since it's clipped in your tank for an extended period. If it isn't coming from your source water, you could always soak some nori in a little fresh salt water for a while, and then test the phosphate levels in the water afterwards.

[cccapt]

Does anyone have a picture of their installation?

I want to add....if you are reading any phos, it's too much. Regular hobby test kits aren't acurate enough at those low readings. You need somthing like a Hanna Low Res Phosphate Colorimeter.
Some good reading here...
http://www.reefcentral.com/forums/sh...readid=1182318

[Ziggy953]

Do you have any sponges in your sump or anywhere on your systems filtration? Sponges can hold nasty stuff and contribute to your PO4 readings as well.

Testing your source water before your RO/DI unit after your RO/DI unit and then after you mix your SW up will eliminate your water as a problem. I had to go through this when I had a hair algae outbreak. As it turns out it was the Salt mix I was using that was putting the PO4 into my system.

[melosu58]

Originally Posted by lando

The two most common causes of PO4 in a tank are source water and food.

This is true. Can you give us some readings on your PWC water.

[MsBeanCtr]

Saturday update.......Well, I purchased a phosphate reactor and media for it and promptly hooked it up. Meanwhile I tested some fresh ro/di water I just did up. It did show a very small amount of phosphates - .10 mg/l. I am planning on testing again later this evening to see if there's much of a change in the tank after installing the phosphate reactor.

At this point I can only assume that it has to do with my feeding schedule and perhaps I need to cut back.

In the mean time...I am planning on 2 pwc's over the next couple of days to lessen the phosphates....do you think a 20% pwc done today and another 20% tomorrow will cause any problems?

Also, one last thought....Our water is fairly soft and I have a low alkalinity reading most of the time. I haven't tested it in the last week. Perhaps I'm reaching at straws at this point, but would this effect the phosphate reading in anyway?

Lastly, hey Kurt....

... I like the chicken bone thing and dancing. Make sure you have someone take pictures so we can all know how to do it ourselves

Sure thing....I'll do it....in exchange for that beautiful new Acanthastrea Lordhowensis you just got.....deal?

[Kurt_Nelson]

I think high alkalinity can effect phosphate tests, but not low alkalinity.

When was the last time you changed out the DI resin in that RO/DI unit? Do you have a TDS meter you can check the output of the filter with? It might be time for a change. When DI resins get completely used up, it's possible for them to actually leach stuff back into the pure water. Could that be possible?

Oh... you might as well go ahead and make soup with the chicken. I'm kinda liking my new addition.

[kay-bee19]

Originally Posted by MsBeanCtr

...I tested some fresh ro/di water I just did up. It did show a very small amount of phosphates - .10 mg/l.

.10ppm PO4 in your RO/DI water is pretty high (since the goal in most reef tanks it to keep it closer to .03ppm); with each PWC you're adding more PO4 into the tank. What's the TDS of the RO/DI water? (ideally it should be 0ppm).

Check your DI resin as Kurt suggested.

[MsBeanCtr]

Wow! I didn't even think of that.....and Kurt & kay-bee you might have hit the nail on the head. I'm due to change the resin....and from the sounds of it, I might be overdue. It's been about 7-8 months since I got it and I'm thinking it's due for a change.

Guess I'll go make some soup.