How often do you change GAC & GFO?

[Batts]

I'm running 1 week GAC and 3weeks GFO using the same reactor.
Just measured 0.04 po4 today and it is the carbon week.
So thinking of if running both at the same time would benefit my system.
If I go that path, wanted to get some opinions on how often do people change their media.

[BENSONSAN]

I don't use gfo only lanthanum chloride so can't comment but i love gac. Look depends on how much you use but i use alot on a 4x2x2 and change out every 5 weeks.

Mate its also extremely variable whats your stock list and tank size a bio load?

[greeni]

Carbon monthly, and GFO Bi=Monthly

[Brett240]

really depends on your own tsank needs though monthly is a good place to start. best to run separate reactors though as the two medias generally run a different flow

[Batts]

Bimonthly as in every two months? I wish I could go that long, I feel my 3weeks GFO time is a bit too long. But changing more often gets a bit pricey.

Lanthanum? Interesting, but I don't understand the export method on that, via skimming? maybe I should do more reading.

How do u tell GFO is exhausted? I read people test their reactor output and if it is not zero po4 they assume it is exhausted. But didn't make much sense to me, is GFO supposed to be that effective that completely removes the po4 in one pass through?

I have a 4foot aqua reef 395, zoanthid dominated mixed reef getting into sps lately. It is packed with corals but fish load is medium (10) I may be a little over feeding as I like my fish fat and healthy.

Some of my corals are getting brown tint lately and film algae on the glass becomes visible every three days. if algae can grow there is excess phospate right? I tested when Glass was covered with algae I still get 0.04 Po4. assuming algae consumes some I should have way more phosphates.
Nitrates varies around 5

I'm also thinking give monthly a go to start with.

[Gats]

GFO totally sucks out the phosphates so it is basically when your phosphates start going up again. I do a glass clean and test phosphate next day (to make sure algae isn't binding it all up). If your flow is right, it will actually remove it all, but it will decrease in effectiveness as long as there's not a big source of phosphate but prefer just to test every month or so and when it's climbing a bit, time to change out.

Cleaning the algae off the glass and testing next day is kinda key IMHO.

[Batts]

Thanks for the comments Gats,
Maybe I got a bit of stuck with the thinking after reading the whole reef keeping made easy thread on trt that if you see algae u have phosphates... For this reason I rarely test for it.

I have done my 3monthly cleaning on Saturday, sucked up all detritus from the o/f box and sump, cleaned all glass including the back glass and made a 140l water change for a 400l system. I siphon my sand bed weekly so most of the waste water was from the sand bed siphon - nice and brown.

Then I added lots of fresh carbon and recommended amount of GFO to two separate reactors and the following photo is what I got today (3days).
I'm using antiphos fe but just bought rowaphos for my next round to see if there is going to be any improvement.

[/URL]

Note that there is no algae growing 2-3cm above the sand bed line, I wonder if this could be a clue... Obviously it is something to do with bacteria but as far as I know bacteria does stuff all for the phosphates.

[Rod the Reefer]

Carbon is only of any real use for a couple of weeks, at the most.

http://www.masa.asn.au/masawiki/index.p ... ted_Carbon

To find out if your GFO is exhausted test the effluent from your reactor. If Po4 isn't lower than your tank it's exhausted. Time to replace or rejuvenate.

Rod.

[Batts]

Good point Rod. I will change my schedule to 2w Carbon, 4w GFO.
It is funny some fancy brand carbon manufacturers claim that their products lasts 3-4months while it is not possible.

Talking of the brands, does it matter what carbon do you use? I recently bought cheapest bulk option carbon. the ones cylindrical shape. My glass algae this week was more than the time I did GFO only.
I didn't soak it in ro before I put in, maybe that's why.

Also I'm using a nano reactor for the GFO, does it matter? It's nano size reactor (350ml) but still can take the recommended amount of GFO for my tank.
I'm hoping changing GFO brand will help my situation, I literally don't feel the existence of the GFO.
If rowaphos doesn't help, I'm going back to phosguard which was the only one I noticed heaps impact on my phosphates (maybe a but too much impact lol)

[pyroay]

Carbon monthly, and GFO Bi=Monthly

Agreed.
I now use UA Phosphate remover instead of GFO because of ease of use, no reactor and pump needed and easy to make exact adjustments on dosing pump but if your running it then bi monthly for GFO and carbon 4 weekly MAX.

Carbon is only of any real use for a couple of weeks, at the most.
Rod.

Rod's right Carbon is really only effective for 5-10 days. Most people use for 1 month to try and get maximum exhaustion out of it and because of the cost of fortnightly changing but results in week 4 are a long way down on the benefits in week 1.