Phosphates and my nano reboot

[Chrisv.]

After a brief hiatus from the hobby, I am rebooting and starting up a nano tank. I plan predominantly rely on biological filtration and frequent partial water changes to manage nutrients in my tank.

My tank has been back up for a month. After my initial cycle, my parameters (measured with the tropic marin kits) are as follows:

pH: 8.2
Sg: 1.025
Temp: 81F (will lower when I add marine life)
NH3/4: <.02 ppm(the lower limit of my test)
NO2: .025 ppm
NH3: 6 ppm
PO4: .3 ppm ( high!)

When I disassembled my previous tank, I cleaned and rinsed a bunch of branch rock and put it on a table outside...for what was meant to be days, but turned into weeks and then before I knew it, two years had passed.

I gave the rock a good rinse and put it in my new 15 gallon nano along with some unused washed sand (carib sea). I added three presumably different (but maybe the same!) microbial starter cultures and a fed pounds of well establish live rock from a tank I trust. The cycle happened within two weeks and parameters seem stable for now.

I'm concerned about the P04 in the tank. I don't have much in the way of algae yet, and there are no fish. I have added two hermits which I have been feeding a few granules of new life spectrum every other day to keep them from starving without algae.

I should mention that I'm using the tropic marin pro salt, and RO/DI water. The water has a 0ppm phosphate when measured with my tropic marin test kit. I've don't three 75% water changes and the PO4 keeps bouncing back to .3, which makes me think it's in the rock and that this is some sort of equilibrium. I didn't do anything like an acid bath when I decommissioned the rock, and now that it's cycled I'm not inclined to go that route.

What do you guys think? Should I attempt to take any corrective measures? I'm torn between adding inverts which will inevitably have zooxanthellae (that will consume PO4 at some rate) and using GFO to bind the phosphate as it comes off of the rocks.

I'd love to avoid a flowing mat of hair algae.

Thoughts?

 

[Reef.]

Ideal time to use gfo before you get corals, I wouldn't start adding anything else into the tank until you get the PO4 under control.

 

[Chrisv.]

Ideal time to use gfo before you get corals, I wouldn't start adding anything else into the tank until you get the PO4 under control.

Would you suggest going nuts with it an over dosing gfo (since there are no corals to annoy?) Or am I asking for issues with organisms that thrive in low nutrient environments (e.g. dinos etc)?

 

[Reef.]

Would you suggest going nuts with it an over dosing gfo (since there are no corals to annoy?) Or am I asking for issues with organisms that thrive in low nutrient environments (e.g. dinos etc)?

Yes, but you really don't need to go that mad, your lvl is only 0.3, a couple of weeks of Rowa will get that down very quickly, not knowing how much your rock is holding but I can't see it being that much if you are only at .3, get it to a reasonable lvl, then add fish and you can slow down on the Rowa before adding corals, Just go slow when you have corals in there.

 

[Chrisv.]

Yes, but you really don't need to go that mad, your lvl is only 0.3, a couple of weeks of Rowa will get that down very quickly, not knowing how much your rock is holding but I can't see it being that much if you are only at .3, get it to a reasonable lvl, then add fish and you can slow down on the Rowa before adding corals, Just go slow when you have corals in there.

How will GFO alter other parameters in the tank? Are there issues with it pulling out other elements, or leaving rust behind (ha!).

 

[Reef.]

How will GFO alter other parameters in the tank? Are there issues with it pulling out other elements, or leaving rust behind (ha!).

Rowa is safe as far as we know, iron is a mineral we need so I guess fish do too, it doesn't affect the other parameters, it's suggested to only rinse it if using a reactor, but I use it in a media bag, I still rinse as a lot of red iron residue comes off it, not meant to be harmful but just makes me feel a little better, there are also a few fines that rinsing helps to get out, so for even just that reason I feel a rinse is worth doing, I use water change water generally or sometimes rodi water.

Just make sure you don't hit zero PO4, as that can cause problems.

 

[Chrisv.]

Preliminary data: 36 hours after adding BRS gfo (not the fancy version) my PO4 levels seem to have dropped from 0.3 to 0.15. Though to be honest, the color match on the Tropic Marin test kit is a bit hard to distinguish. Time for a hanna checker I guess.

 

[Reef.]

Preliminary data: 36 hours after adding BRS gfo (not the fancy version) my PO4 levels seem to have dropped from 0.3 to 0.15. Though to be honest, the color match on the Tropic Marin test kit is a bit hard to distinguish. Time for a hanna checker I guess.

nice, keep in mind the Rowa will exhaust fairly fast at first with your high lvls, so I would change a bit sooner than you normally would until your lvls get near where you want them.

Yeah I'm still undecided on a good PO4 kit, keep getting put off the Hanna as some say they are not great, but I guess I'll have to try one for myself, think I might give the nyos PO4 test kit a try first, read a few good reviews, my tank being LPS I might be fine with that one.

 

[Chrisv.]

I will be testing every 24h and when it starts to drift back up, I will switch it out. I'm also going to be putting together a last minute QT system which will get water changes using water from my tank, which should facilitate a substantial number of WCs in my display.

I find it very hard not to "a bit optimistic" when it comes to color matching on my test kits. 0.3 and 0.2 look so close to one another. I find myself biasing my interpretation of the color chart, which is no good. I love the idea of the checker being quantitative and non-subjective.

I'll update this thread as things progress in case it is useful for anyone in the future.