Phosphates

[Joecruel]

Trying to figure out where I want phosphate levels to be in a planted aquarium.  I have a relatively planted aquarium and due to over adding iron and over feeding I believe  to the 55 gallon aquarium I now have Moderate hair algae Siamese algae eaters are working on it a little but when investigating more water parameters I noted the high phosphate and began daily water changes which is reducing it but I really don’t understand where that level should be .  Seems to be a topic which is ignored often. Don’t see much if any info around on the topic . 

[Lizzie Block]

I think less than 1ppm? Could be wrong. But also the plants will take up the phosphates. It's not a parameter I ever consider unless I set up a new tank because it causes diatom algae.. which eventually subsides as the algae takes up mostly all the phosphates. The algae dies off and then I rely on my plants for the rest. If I were in your shoes, I'd just cut back on ferts for a couple weeks and see if that makes a difference

[tolstoy21]

I saw a video I can no longer find from a Seachem rep (or maybe it was a Fluval rep) in which they explained that it's advantageous to keep an specific phosphate to nitrate ratio (to the best of ones ability) for the best plant growth (and less algae as a result), and that without an appropriate phosphates level plants can't as effectively uptake nitrates. The ratio believe was 1:10, phosphate to nitrate, but don't quote me on that. 

Like everything, I'm sure this is a much debated topic, but maybe start by trying to maintain near 1ppm.  Watch that for a few weeks and see what the results are -- do things get better or worse? Adjust accordingly, then wait and see what direction that moves things in.

As with all things, it can all be confusing as you get advice like 'too much and you get algae' then you hear 'too little and you get algae'.

I found that if I kept things around 1ppm, not fretting if i was over or under (within reason) and everything was fine.

[Daniel]

@KBOzzie59 posted a link to a webinar where I believe this was mentioned as the 'Redfield Ratio'

Here is a chart

And mg/l translates to ppm directly.

[KBOzzie59]

PMDD :: aquarium fertilizer :: Redfield ratio calculator

AQUARIUM-FERTILIZER.EU

 

[varanidguy]

On 10/30/2020 at 6:18 AM, tolstoy21 said:

I saw a video I can no longer find from a Seachem rep (or maybe it was a Fluval rep) in which they explained that it's advantageous to keep an specific phosphate to nitrate ratio (to the best of ones ability) for the best plant growth (and less algae as a result), and that without an appropriate phosphates level plants can't as effectively uptake nitrates. The ratio believe was 1:10, phosphate to nitrate, but don't quote me on that. 

Like everything, I'm sure this is a much debated topic, but maybe start by trying to maintain near 1ppm.  Watch that for a few weeks and see what the results are -- do things get better or worse? Adjust accordingly, then wait and see what direction that moves things in.

As with all things, it can all be confusing as you get advice like 'too much and you get algae' then you hear 'too little and you get algae'.

I found that if I kept things around 1ppm, not fretting if i was over or under (within reason) and everything was fine.

This is about the ratio I started with, but have since adjusted. I have a tank that's phosphate hungry. I'll dose 4 ppm and end the week with 1 ppm or less.

 

Insofar as nutrients causing algae in planted tanks, I'd wager over or under dosing micro nutrients would have more of an impact over macros, providing water changes are being kept up.

[tolstoy21]

You know, to be completely honest I don’t even check my phosphate levels anymore. Or much else , just nitrate every now and then.

i used to dose with all the seachem products on an auto doser, and that worked well in terms of plant growth. At that time I ran CO2 and checked all my levels on a routine basis. 

But since then I simplified everything. I turned my lights down and just plant swords and crypts and anubias and java fern (easy slower growing stuff) and dose twice a month with a dry fert. I’ll supplement that with root tabs every three or so months  

Everything is green and happy and growing huge. Don’t do much but watch it grow at this point.

Edited November 2, 2020 by tolstoy21

[Joecruel]

Update... so after several water changes to lower the phosphates, the use of easy carbon daily for a week or so, and feeding more brine and frozen than fish food,  as well as the Siamese algae eaters,  and slowing down on the easy green . I have attained control of the black beard algae that was getting a little out of control ... 

[Joecruel]

Now I’m only worried the Algae eaters might starve off .