Nitrate = 1 - 2.5 phosphate = 0.2

[Jemm]

Nitrate = 1 - 2.5 phosphate = 0.2

Phosphate not going down

Skimmer = bubble magus c 3.5
Chaeto refugium, strong horticulture light
Lots of live rock
Tank age = 2 years
Hardly any coralline algea

Alk = 10.2
Mag = 1320
Cal = 440


I have just started dosing nitrate as nitrate was 0 a few days ago ,

How can I get phosphate down

 

[Saltyreef]

Reduce phosphate with GFO easily.
Im surprised your chaeto isnt taking care of it. Do you get good growth?

 

[IslandLifeReef]

While you PO4 is on the higher side of what a lot of people say is normal, it isn't so high that you need to bring it down.

Are you experiencing any issues that you think are related to the PO4?

 

[Jemm]

There looks to be a green film algea growing over my rocks,

Also my birdsnest looks very very pale it was a solid green when I bought it

 

[Jemm]

Yea I thought cheato would take care of it, it does grow but I'm thinking that because there was no nitrate it could not grow and uptake phosphate

 

[IslandLifeReef]

Yea I thought cheato would take care of it, it does grow but I'm thinking that because there was no nitrate it could not grow and uptake phosphate

I agree with you on this. Your system is probably NO3 limited. Now that you are dosing NO3, I would wait a month or two to see if the cheato starts growing more and if there is any movement in the PO4. Remember that PO4 can bind to the rock and substrate, so it may take a while for the PO4 to come down. As the PO4 is removed from the water, it will then leach from the rock and substrate to try to reach an equilibrium.

I'll say again, give the NO3 dosing a month or two to see if that helps. Based on your reply above, there isn't an emergency that needs to be corrected, so don't create one by changing too many things all at once.

 

[Jemm]

Thanks that sounds just the ticket wasn't sure how long it'd take will report back in a month !

 

[Saltyreef]

Dont over do it on nitrates though.
Slowly working your way to 10ppm is a good limit for now.
Ask me how i know.....

 

[Jemm]

Lol, how do you know..

I think I might have caused a little stn on one branch of my birdsnest from dosing nitrate. I'm using potassium nitrate, with the belief that chaeto will use up excess potassium

 

[Saltyreef]

Tank crash from nitrate overdose. Lost all my hoarded old schools and high ends
Did math wrong. 5ppm target ended up as 50+ ppm

 

[jda]

If your chaeto is not growing, do you change water or dose iron? If you do either, then I am at a loss. If you do neither, then chaeto needs iron and a few other traces to grow, so get some Ferrion or change some water to replace the iron. You also need to harvest it often and keep the ball nice and loose.

My chaeto can mostly keep my P nice and low where I like it, but if I have an influx of organics, then it gets behind and I need to help it out.

If you are feeding a ton, then your coral have all of the nitrogen that they need from the ammonia/ammonium. Micro algae and most SPS cannot use no3 anyway, but they do need nitrogen from the ammonia/ammonium, but just a trace is fine. There are other things in your tank that need no3, like the chaeto, but even .1 or .2 is good if you are feeding a lot.

Edit: residual levels of N and P have no bearing on chaeto growth. Availability does. I have 1-3 ppb of P and .1-.2 N and I have to remove 5 gallons of chaeto quite often (more than monthly). You don't need high N and P levels to grow chaeto and it actually grows better with lower levels and I found that it breaks apart and dies with higher levels.

 

[Jemm]

It is growing but it does go through phases where it stops, it recently stopped until I dosed some nitrate and seems to have picked up again

What you are saying would make perfect sense, as it seems to be running out of things it needs

I am running a calcium reactor and trying for no water changes

What would you Reccomend as a cheap way to dose iron

Would the foods I add not contain iron and other elements like iodene in themselves ?

I was looking at tritons infusion what are your thoughts on that or would you say it is not needed

 

[SMSREEF]

Micro algae and most SPS cannot use no3 anyway

Excerpt from:
Nutrient uptake in the reef-building coral Acropora palmata at natural environmental concentrations-John C . Bythell


The capacity for simultaneous uptake of nitrate and ammonium from enriched seawater has been demon- strated for both intact corals (D'Elia & Webb 1977, Wilkerson & Trench 1986) and isolated zooxanthellae (D'Elia et al. 1983).This study indicates that simultane- ous uptake also occurs at natural seawater concen- trations. This net uptake contributes approximately 30 % to the average daily nitrogen requirement for tissue growth, gamete production and dissolved organic nitrogen production (Bythell 1988).

http://www.int-res.com/articles/meps/68/m068p065.pdf

 

[jda]

Honestly, the cheapest and easiest thing that you can do is to change some water. You will spend more time and money with supplements and still never know if you got it right unless you spend even more time and money getting a pile of test kits.

 

[nereefpat]

Water changes might help the chaeto grow, which would slowly lower the P.

But, there are much better ways to lower phosphate. One easy way is this:

Reduce phosphate with GFO easily.

Just use small amounts and test phosphate frequently.

Water changes don't directly work well at all for lowering phosphate. If the water has 0.2 ppm phosphate, then the rock and sand is full of it too. Changing water, and it would take huge water changes, would drop the phosphate level, but the rock and sand would just leach phosphate out into the water column.

 

[jda]

Yup. Water changes are not an effective way of directly lowering P levels, but can help to maintain them. You just change water for other reasons. If the water changes allow the chaeto to grow well, then this can lower P in good amounts.

 

[jda]

Also, I do like my P lower than .2, but some cuation... don't mess with it unless you have a tool like a Hannah Ultra Low to test. Lastly, there is no urgency to lower it, so go really slow and use an abundance of caution. You can do more harm lowering it too fast, or having the water level amount bounce up and down with quick removal and then aragonite unbinding than you can have by not doing anything. Read up and understand how aragonite binds and unbinds P and how once you lower the water level that the rock/sand will unbind and raise it again - the rock/sand acts like a reservoir, so you want to remove it at about the same level that the rock unbinds, which takes small amounts.

Don't cut back on feeding. Lowering residual levels of P is fine, but cutting back on feeding with no availably can truly harm the corals.