Overdosing Po4 remover

Mekaeel

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Hello Uncle Hennie :)

Is it possible to overdose granular phosphate remover? eg. Rowaphos recommends X amount of media for 1000l of water.

Reason i ask, if you look at the Zeovit method, tanks are taken to extremley low, to nutrient poor enviroments by eliminating phosphates and dosing of Bacteria etc...
Now can the same/similar results be achieved by overdosing phosphate remover? eg. double or thriple the amount of Po4 media?

What are the side effects of overdosing? I do understand that with SPS corals(in my case) when very low nutrients, to nutrient poor enviroments are achieved it is important not to keep your Alk in the range of 6.5-8.5 DKH, else TN.

Thanks in advance
Mekaeel
 
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Hi Mekaeel,

Yes, I think you could achieve very-low PO4 levels by using higher than recommended dosages of phosphate remover, but like everything else in our tanks I would try to keep it natural, and not drop the levels below that of NSW.... Your corals need phosphate to live, and although you can get them to colour up very nicely if the PO4 level is low, you do run the risk of starving the corals if you keep the levels abnormally low for a long time.

If you do want to try it I would suggest that you firstly get a very accurate phosphate measuring instrument, and, as with everything else, make the changes very slowly whilst measuring. Oh, and I would only use the iron-based type, and not the aluminium based products.

Let us know what happens, if you do decide to take the chance.

Hennie
 

Mekaeel

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Hi Mekaeel,

Yes, I think you could achieve very-low PO4 levels by using higher than recommended dosages of phosphate remover, but like everything else in our tanks I would try to keep it natural, and not drop the levels below that of NSW.... Your corals need phosphate to live, and although you can get them to colour up very nicely if the PO4 level is low, you do run the risk of starving the corals if you keep the levels abnormally low for a long time.

If you do want to try it I would suggest that you firstly get a very accurate phosphate measuring instrument, and, as with everything else, make the changes very slowly whilst measuring. Oh, and I would only use the iron-based type, and not the aluminium based products.

Let us know what happens, if you do decide to take the chance.

Hennie
Excellent, thank you Hennie :) Keeping in mind i've started a very heavy feeding regime, about 5 times a day on a SPS dominated system.

Another question. Some guys change Phosphate media every month where as some change every 4-6 months.What would you recommend? My guess it all depends on the amount of phosphates that are being consumed (test kit required once again).Correct?
 
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Some guys change Phosphate media every month where as some change every 4-6 months.What would you recommend? My guess it all depends on the amount of phosphates that are being consumed (test kit required once again).Correct?
Correct :slayer:... and it will have to be a very accurate, reliable test kit, not one of the hobby-type colorimetric ones. Look at getting one of the Hanna photometers, if possible (and if you have lots of money :whistling: )

Hennie
 

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Correct :slayer:... and it will have to be a very accurate, reliable test kit, not one of the hobby-type colorimetric ones. Look at getting one of the Hanna photometers, if possible (and if you have lots of money :whistling: )

Hennie
Hello Hennie

Not all Colorimetric Test for phosphate are unreliable because Tunze have a high sesitivity test for phosphate which measures in the range of 0.01-0.25mg/l P or 0.03-0.77 mg/l PO4 wich retails at about R 1300.00 for 100 tests so there are alternatives.
The only draw back is that I only bring them in on special order as there are expiry dates. I think whoever uses it will be well satisfied.

George
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Mekaeel

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Correct :slayer:... and it will have to be a very accurate, reliable test kit, not one of the hobby-type colorimetric ones. Look at getting one of the Hanna photometers, if possible (and if you have lots of money :whistling: )

Hennie
+- figure on the Photometer Hennie? I was thinking in the mean time Lamoete or Deltec. Those kits have the extra decimal value.
I've tried the TM Po4 test kits, bloody waste.
 
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Not all Colorimetric Test for phosphate are unreliable because Tunze have a high sesitivity test for phosphate which measures in the range of 0.01-0.25mg/l P or 0.03-0.77 mg/l PO4 wich retails at about R 1300.00 for 100 tests so there are alternatives.
Thanks for the info, George :thumbup:

Do you know if this kit can measure organic phosphate/phosphorus as well as inorganic (most test kits can only measure inorganic...)

Also, can you please tell us what the resolution and accuracy of this kit is. I think it's pretty important to have a high resolution (i.e. able to detect small level differences) and decent accuracy if one approaches the lower limits of natural sea water phosphate concentration (0.07ppm - 0.03ppm), as going too low will stress, and eventually kill, the corals in the tank. What I'm saying is that it won't be very helpful to have a kit that can measure down to 0.001ppm, if it only has a resolution of 0.1ppm, or an accuracy of 0.5ppm...

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Or try the test kit George mentioned - Tunze has a very good reputation, and if their test kits are half as good as their pumps it might be worth it :)

Hennie
 

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Thanks for the info, George :thumbup:

Do you know if this kit can measure organic phosphate/phosphorus as well as inorganic (most test kits can only measure inorganic...)


Hennie
As far as I know any oxygenated molecule is a eg PO4 is an organic one and the p stands for the inorganic thats why with this kit you can do iether or.
These test kits are only ordered as required because of the expiry date.

George
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As far as I know any oxygenated molecule is a eg PO4 is an organic one and the p stands for the inorganic thats why with this kit you can do iether or.
As far as I know, most (all?) colorimetric test kits measure inorganic phosphorus, and not phosphate. To quote Dr. Randy Holmes-Farley:
[FONT=Times New Roman, Times, serif]A final point is that organic phosphates will not be detected by most test kits. Those that do detect organic phosphates (e.g., Hach PO-24) break the phosphate off of the organic compound and thereby convert it into inorganic orthophosphate prior to testing. However, these kits are tedious and expensive, and not for every hobbyist. [/FONT]
and...

[FONT=Times New Roman, Times, serif]Many of these organic phosphate compounds will be readily removed from a tank by skimming. Export of organic phosphates is the major way that skimming can result in reduced inorganic orthophosphate levels in a tank. Orthophosphate ions themselves are not significantly removed via skimmate (since they do not adsorb onto an air/water interface), but organic phosphates can be removed before they are converted into inorganic orthophosphate. [/FONT] [FONT=Times New Roman, Times, serif]An important point about organic phosphates is that they will mostly not be impacted by phosphate-binding materials sold to the aquarium hobby. Consequently, while these products may do a fine job of reducing inorganic orthophosphate, they may not help an algae problem that is caused primarily by organic phosphates.[/FONT]
On a different tack, has anyone ever heard of using Magnesium/manganese to adsorb phosphate? I recently came across this interesting abstract of a science paper:
Abstract

Adsorptive properties of MgMn-3-300 (MgMn-type layered double hydroxide with Mg/Mn mole ratio of 3, calcined at 300 °C) for phosphate were investigated in phosphate-enriched seawater with a concentration of 0.30 mg-P/dm3. It showed the highest phosphate uptake from the seawater among the inorganic adsorbents studied (hydrotalcite, calcined hydrotalcite, activated magnesia, hydrous aluminum oxide, manganese oxide (δ-MnO2)). The phosphate uptake by MgMn-3-300 reached 7.3 mg-P/g at an adsorbent/solution ratio of 0.05 g/2 dm3. The analyses of the uptakes of other constituents (Na+, K+, Ca2+, Cl−, and SO2−4) of seawater showed that the adsorbent had a markedly high selectivity for the adsorption of phosphate ions. Effects of initial phosphate concentration, temperature, pH, and salinity on phosphate uptake were investigated in detail by a batch method. The phosphate uptake increased slightly with an increase in the adsorption temperature. The adsorption isotherm followed Freundlich's equation with constants of logKF=1.25 and 1/n=0.65, indicating that it could effectively remove phosphate even from a solution of markedly low phosphate concentration as well as with large numbers of coexisting ions. The pH dependence showed a maximum phosphate uptake around pH 8.5. The pH dependence curve suggested that selective phosphate adsorption progresses mainly by the ion exchange of HPO2−4. The study on the effect of salinity suggested the presence of two kinds of adsorption sites in the adsorbent: one nonspecific site with weak interaction and one specific site with strong interaction. The effective desorption of phosphate could be achieved using a mixed solution of 5 M NaCl + 0.1 M NaOH (1 M = 1 mol/dm3), with negligible dissolution of adsorbent. The adsorbent had high chemical stability against the adsorption/desorption cycle; it kept a good phosphate uptake even after the repetition of the seventh cycle.
Hennie
 

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