Algae - Not necessarily PO4

[geoffrey]

Many of us tend to put the blame for our algae on high PO4 and NO3, including myself. I recently had my 3rd serious bout of BBA and my water parameter indicates high PO4 at 2ppm and NO3 at 20ppm. Immediately one would assume that both were culprits for the uninvited guest.

What turns out instead was actually limiting CO2 as a result of the large amount of light that I supplied to my tank. Since it's difficult for me to increase the CO2 in my tank significantly because a reactor is used, I also lowered my lights to help. That has worked within weeks. After hacking and pruning, no new sign of BBA has appeared.

One thing I did not do was to eliminate NO3/TE/Mg. I continued my regular dosage of nutrients after my weekly 50% water change. Instead, I reduced dosage of KNO3 by half. As for PO4, I was unable to lower it because there was a positive net balance (base is supplying more than what the plants uptake).

Now that BBA is gone, my water parameters still measures PO4 at 2ppm and NO3 at 10ppm, and Fe at 0.1ppm. The only different is NO3 has come down from 20ppm. Plants became healthier again and my E. schlueteri has 4 plantlets now.

I hope my experience will give others with the same predicament an open mind on how algae can be eliminated, and most of the time, it may not be thru eliminating PO4 and NO3 (reduce but do not eliminate).

Lastly, small SAEs do eat BBA. I accused them as inefficient algae crews only to realise later that my previous SAEs were Flying Fox instead.

[DEA]

yes, you are right
imo why everyone jumps on phosphate is because of the sears-conlin paper
in which they ONLY measured the effect of phosphate on algae growth
the effects of the rest of the nutrients is pretty much undetermined in a scientific manner
but basically, any imbalance can give you algae

even if you have a perfect nutrient balance, you might still have some algae
that's why i still like to keep biological algae control in the tank

as for the saes
i noticed you have small ones
my big ones (when i still had them) were so big they hurt pulling on my arm hair when i fed them []
and of course they ignored the algae

[Allen_1971]

Geoffrey,

sounds like you're due for an upgrade to your reactor... go with a good one, you won't regret it.

[Plantbrain]

A non CO2 tank is a limited tank.

A Fertilized tank is a CO2 enriched one.

Fusing the two methods together seemed like a good idea but if you think about it, if you remove one limitation that holds plant growth back, you may as well remove all of them.

Of the two biggest issues for algae, NO3 too high or too low and CO2 too low have to be the largest parameters that give folks trouble.

NH4 is in there also. Low O2 is also part but it relates to plant health and production of O2 by the plants.

Regards,
Tom Barr

[Plantbrain]

In defense of Paul's orginal artilce:
They state to limit PO4 down to 0.2ppm, not eliminate it completely.
Folks think "bad, kill it it all." Sort the USA's Foreign policy here at the present time

But most of the 0.2ppm of PO4 often is organically bound and not really available to the plants or algae. Inorganic PO4 is available and is rapidly used up. Test kits often test for total PO4, not one or the other.

But low test residuals are often seen in many tanks. If you do large weekly water changes and dose with PO4, you find no PO4 after a few days/hours in many cases.

Regards,
Tom Barr

[Mortadelo]

Tom, would you dose PO4 in a tank testing 0,2 ppm PO4 and algae problems? (assuming K, CO2, traces and NO3 are there).

Is there a way to know whether PO4 testing reads usable or unusable PO4?.

Regards.

[Plantbrain]

This is what'd I'd do.
First double check the CO2.
Second remove the algae/prune.
Do a water change.
Add nutrients back in the tank(PO4 included).

Test kits are not always right nor that accurate in many cases.
Simply adding PO4 might help enough to turn the tide, BUT........ removing the algae and double checking the CO2 and adding fresh KNO3 traces etc back in will remove doubts that it's something other than PO4. This also accounts for other issues like test kit error/inaccurate readings etc.

http://www.aquatic-plants.org/fert/e...st_index1.html

PO4 will build up if the plants are limited by say NO3 or CO2 etc.

CO2/NO3 are the two biggest offenders for the algae.

Regards,
Tom Barr




Regards,
Tom Barr

[geoffrey]

Allen,

I think I can still manage with the same reactor to give about 30ppm of CO2. Contemplating on another tank so the reactor can hold : )

Tom,

Thanks for the help.