School me on Phosphates!

[arrowheadpuffer]

#1) What test kit is good? I use to have one and the range was to broad to get a good reading on a reef. What would people here recommend?

#2) Phosphate remover: Which to use and wheres the best price? How long does one treatment last? This stuff doesn't seem cheap!

#3) Reactor, is the Two Little Fishies Phosban Reactor 150 is a good choice? Could I run two off the same pump, one for carbon one for phosphate remover? What pump to use?

#4) How much does kalkwasser help with phosphate? I top off almost all the time with kalkwasser.

[WI reefer55]

also am intrested

[Necsones]

1- best testing kit for phosphates is hanna phosphate photometer. Im still looking for another good one my self.

2- Phosphate remover you can get at bulk reef supply.. think a ton of people on here get it from there. I get the High Capacity Ferric Oxide and change it out about once a month.

3- two little fishies is a good one and also alot of people are using and you can link two to one pump. And again Bulk reef supply has a 2 piece set up just for that. (i dont have tho)

4- idk cus i dont dose kalkwasser

[sohal1025]

I would go with the two little fishies reactor also.

[arrowheadpuffer]

Is that the $250+ Hannah tester? I think I am looking for a color chart type affordable test kit...

Are there any risks with GFO, I think I read something about it a while ago, and also that it can get full and leech the phosphates back out, can anyone explain?

Do I need a separate reactor for carbon or can I mix both GFO and carbon in the same reactor.

[Frogmanx82]

I like the elos test kit for phosphates. It is good for low levels.

[Randy Holmes-Farley]

School me on Phosphates!

For some in depth schooling, you can check out these articles:

Phosphate and the Reef Aquarium
http://reefkeeping.com/issues/2006-09/rhf/index.php

Iron Oxide Hydroxide (GFO) Phosphate Binders
http://reefkeeping.com/issues/2004-11/rhf/index.htm

What Your Grandmother Never Told You About Lime
http://reefkeeping.com/issues/2005-01/rhf/index.htm


for example, to your specific question on limewater (from the last article):


http://www.reefkeeping.com/issues/20...f/index.php#15

What Else Does Limewater Do In An Aquarium? Reduce Phosphate

Many reefkeepers accept the concept that adding limewater reduces phosphate levels. This may be true, but the mechanism remains to be demonstrated. Craig Bingman has done a variety of experiments related to this hypothesis, and has published them in the old Aquarium Frontiers. While many aquarists may not care what the mechanism is, knowing it would help to understand the limits of this method, and how it might best be employed.

Habib Sekha (Salifert) has pointed out that limewater additions may lead to substantial precipitation of calcium carbonate in reef aquaria. This idea makes perfect sense. After all, it is certainly not the case that large numbers of reef aquaria will exactly balance calcification needs by replacing all evaporated water with saturated limewater. And yet, many find that calcium and alkalinity levels are stable over long time periods with just that scenario. One way that can be true is if the excess calcium and alkalinity that such additions typically dump into the aquarium are subsequently removed by precipitation of calcium carbonate (such as on heaters, pumps, sand, live rock, etc.).

It is this ongoing precipitation of calcium carbonate, then, that may reduce the phosphate levels: phosphate binds to these growing surfaces, and becomes part of the solid precipitate. The absorption of phosphate from seawater onto aragonite is pH dependent, with the binding maximized at around pH 8.4 and with less binding at lower and higher pH values. If the calcium carbonate crystal is static (not growing), then this process is reversible, and the aragonite can act as a reservoir for phosphate. This reservoir can inhibit the complete removal of excess phosphate from a reef aquarium that has experienced very high phosphate levels, and may permit algae to continue to thrive despite having cut off all external phosphate sources. In such extreme cases, removal of the substrate may even be required.

If the calcium carbonate deposits are growing, then phosphate may get buried in the growing crystal, which can act as a sink for phosphate, at least until that CaCO3 somehow dissolves. Additionally, if these crystals are in the water column (e.g., if they form at the local area where limewater hits the tank water), then they may become coated with organics and be skimmed out of the aquarium.

An alternative mechanism for phosphate reduction via limewater may simply be the precipitation of calcium phosphate, Ca3(PO4)2. The water in many reef aquaria will be supersaturated with this material, as the equilibrium saturation concentration in normal seawater is only 0.002 ppm phosphate. The supersaturation of calcium phosphate will be even higher in the high pH/high calcium fluid present where limewater enters reef aquaria. The locally high pH converts much of the HPO4-- to PO4---, and it is the concentration of PO4--- that ultimately determines supersaturation. That high supersaturation may tip the balance to precipitation of calcium phosphate, just as too much limewater all at once can tip the balance to precipitation of calcium carbonate. As with CaCO3, the precipitation of Ca3(PO4)2 in seawater may be limited more by kinetic factors than by equilibrium factors, so it is impossible to say how much might precipitate under reef tank conditions (without, of course, somehow determining it experimentally).

As with the precipitation of CaCO3 containing some phosphate, if these calcium phosphate crystals are in the water column (e.g., if they form at the local area where limewater hits the tank water), then they may become coated with organics and be skimmed out of the aquarium.

[Snookster]

Great info Randy - Thanks

[Arrgh Matey]

One thing to keep in mind is you can get a false negative from a phosphate test on tank water (same as Nitrates). If you have a lot of algae, it tends to "suck" the phosphates and nitrates in and lock them up.

That was the hardest thing for me to figure out. I had a ton of algae, but phosphate and Nitrate test would read zero. Then one day I tested the batch of saltwater I used for a water change and phosphate was off the scale. Another reason not to use tap water for water changes.

[Randy Holmes-Farley]

I wouldn't call that a false negative. That implies an actual testing problem, which is not the case. If the concern is the phosphate concentration itself (with respect to coral calcification, for example), it is a perfectly adequate result.

It can certainly be true that a lot of algae (problem microalgae in the display tank or desirable macroalgae in a refugium) can keep the phosphate levels low, but it can still be a viable approach to deter the problem algae by intercepting the phosphate before the algae gets it.

Great info Randy - Thanks

You're welcome.

Happpy reefing.

[arrowheadpuffer]

Thanks, I have seen those reef keeping articles, they are very helpful, but I am really not the chemistrey sort, I took physics in college and HS instead... So I am looking for a simple answer.

To run GFO or not? I assume running it every other month couldnt hurt?

To top off with kalk or not? I assume as long as my pH doesnt get over 8.2-8.4 its not a problem?

GFO and cabon in the same reactor? Problem or no? (run for 30 days every other month)?

[rkb]

GFO- yes, and change about every couple months. The reagent PO4 tests are not very accurate so just monito your system. When you start using GFO you'll find yourself scraping a lot less.

GFO and carbon in the same reactor- no, the carbon is good for around a month while the GFO lasts a little longer. I run two Phosban 150s, one Chemi-pure the other GFO. They are run off the same pump, I think it is a Rio 800. On both reactors I run at a low flow rate of around 30gph. The proper amount of GFO is around one gram per gallon. Depending on your system volume, you may have lots of room in the reactor. Do not fall to the temptation of filling your reactor up, overdosing with GFO can drop your alkalinity.

[arrowheadpuffer]

thanks! So am I to understand that the GFO should be kinda suspended from the flow in the reactor, tumbling around? Is this the same with the carbon? Wont waste and stuff like that get stuck in the reactor, kinda like having a canister filter on a reef?

[EdSnyder]

Originally Posted by arrowheadpuffer

thanks! So am I to understand that the GFO should be kinda suspended from the flow in the reactor, tumbling around? Is this the same with the carbon? Wont waste and stuff like that get stuck in the reactor, kinda like having a canister filter on a reef?

Yea I have had dead hair algae clog mine up really badly.

[Plan>B]

Originally Posted by rkb

GFO- yes, and change about every couple months. The reagent PO4 tests are not very accurate so just monito your system. When you start using GFO you'll find yourself scraping a lot less.

GFO and carbon in the same reactor- no, the carbon is good for around a month while the GFO lasts a little longer. I run two Phosban 150s, one Chemi-pure the other GFO. They are run off the same pump, I think it is a Rio 800. On both reactors I run at a low flow rate of around 30gph. The proper amount of GFO is around one gram per gallon. Depending on your system volume, you may have lots of room in the reactor. Do not fall to the temptation of filling your reactor up, overdosing with GFO can drop your alkalinity.

I was wondering on the amount/sizing needed for my system and GFO.... now I just need to find out about much in volume 350 grams is

[arrowheadpuffer]

bump

[Frogmanx82]

I'm still trying to figure out the GFO. I am running 5 oz GFO mixed with 5 oz carbon. They are both the premium grades from BRS. They are running in an intank filter box in a media bag with floss as a prefilter.

While you say GFO lasts longer than carbon, I guess it really depends on the phosphate loading. I put the GFO in on Nov 1 and phosphates are still checking below 0.01 on the Elos test kit.

Flow on the filiter is 250 gph in a 90 gallon tank.

I'll see when the phosphates begin to rise and adjust my ratio with the carbon based on that so they both are changed monthly.

[bertoni]

I mixed carbon and GFO regularly. The top layer of the filter can be tumbling, gently, but not all the media. I changed the media once a month. The carbon probably gets exhausted more rapidly, and the GFO will be covered by bacteria fairly quickly.

[arrowheadpuffer]

Originally Posted by bertoni

the GFO will be covered by bacteria fairly quickly.

Is that a issue (kinda like having a bio filter on a reef)? or do the pros out way the cons?

[bertoni]

It's exactly like having a bio-filter, although it's usually small enough not to be a problem. The GFO isn't going to adsorb much phosphate after it's covered with bacteria, though.

[offroadodge]

i use Two Little Fishys 150 reactor with ROWAPHAUS. No problem with phosphates