Is phosphate and nitrate dosing a must?

[chua]

Hi all,

i will like to know if the above two required dosing.

I had read from some articles that the imbalance of these two are one of the main reasons for algae problem. In addition, the food the we provide and the fishes that we have can also produce these two elements.

Hence, can we not dose these two elements if our tank is doing fine.

Can i have a poll here to see if anyone is dosing the above two elements and what is the amount.

Thks.

[Sleepy_lancs]

I am not dosing NO3 at the moment. But I am dosing PO4 at about 4ml per week at 0.44 ppm.

To dose or not depends on your water conditions. As long as you have about 5 - 10 ppm of NO3 and 0.2 - 1.0 ppm. You should have sufficient. Most important is to read the response from the plants.

[PeterGwee]

Unless you have loads of fishes, feed very heavily or high NO3 in the taps (In singapore, the max you could get is only 15ppm which would be gone in 3-5 days in a high light CO2 tank.), you should need to dose every 2-3 days. Doing the estimative index method is easy and does not require you to test much except for the pH/KH/CO2. Dosing every 2-3 times a week prevents deficiencies whereas large water changes corrects the excess in case the plants are not using that much or are not growing well. The frequency of dosing depends on the amount of light, bioload, plant load, plant type, amount of critters and NO3/PO4 in the tap.

Currently I am dosing 10ppm of KNO3 2x a week and 1 rice grain of KH2PO4 2x a week for my 2ft tank.

Regards
Peter Gwee

[steve]

hi guy,

Happy New Year to all of you !

Can i know where did you buy KNO3, KH2PO4 and PO4?
what is the brand of the N3 test kit u using? I bought
TetraTest NO3, but it does not give me 5ppm resolution.
first colour is 0ppm, secong colour is 12.5ppm.

[Kingfisher]

I add just a few grains of KH2PO4 a week for my 4ft tank. No NO3 added as my tank has high enough NO3.

[Sleepy_lancs]

[quote:f296866c2b="steve"]hi guy,

Happy New Year to all of you !

Can i know where did you buy KNO3, KH2PO4 and PO4?
what is the brand of the N3 test kit u using? I bought
TetraTest NO3, but it does not give me 5ppm resolution.
first colour is 0ppm, secong colour is 12.5ppm.[/quote:f296866c2b]

Hi Steve,

Most people here buys the chemicals from Dr Mallack. You can check his store from the lfs listing. Some of them use commercial brew which are namely SeaChem and TropicaGrow. I use Lab grade stuff.. so its rather impossible for you to get. Sorry.

For testers, again many people uses different brands. Most commonly used here is AP. I use Sera. SeaChem does make good test kits too but they are rather pricey.

Hope I have answered your questions. If you want more info, PM me.

[juggler]

Personally I feed my fish a lot with bloodworms and tetra bits. But the food seem to provide enough of the NO3 (10~20ppm) but not enough of the PO4.

So I need to dose about 1.5 ppm PO4 weekly (dosed twice at 0.75ppm each time).

The other important nutrient is K. Remember to dose that as well. I put 10ppm K each week.

[chua]

Hi juggler,

If i am not mistaken, mg ia also another important element. Do we need to dose that too?

Sorry. A little bit of chemistry here. If KNO3 is added. This mean that it will provide both K and NO3 to the tank. Then for KH2PO4, it will provide PO4 to the tank. What is KH in the chemical name?

What is the chemical name if we want to dose k and mg into the tank. If we add KNO3 to obtain the required k level, we may add excess NO3 into our tank at the same time. Hence, i believe that this chemical is not use for dosing just k.

Lastly, can i use the chemical that is found in the chemistry lab instead of the common Dr Mallick?

Thks for the help juggler.

[geoffrey]

Firstly, most of you may not know that Juggler has installed, in all his tanks, NO3 machines. If he doses, its always very little

Chua, KH refers to potassium and hydrogen. You can get K alternatively from K2SO4. Mg from MgSO4.

Yes, you can use those from labs. However, those in labs are laboratory grade, hence expensive.

[Sleepy_lancs]

[quote:9e5bb1e163="chua"]Hi juggler,

If i am not mistaken, mg ia also another important element. Do we need to dose that too?

Sorry. A little bit of chemistry here. If KNO3 is added. This mean that it will provide both K and NO3 to the tank. Then for KH2PO4, it will provide PO4 to the tank. What is KH in the chemical name?

What is the chemical name if we want to dose k and mg into the tank. If we add KNO3 to obtain the required k level, we may add excess NO3 into our tank at the same time. Hence, i believe that this chemical is not use for dosing just k.

Lastly, can i use the chemical that is found in the chemistry lab instead of the common Dr Mallick?

Thks for the help juggler.[/quote:9e5bb1e163]

K in KNO3 isn't alot. You need more than what is added by NO3. If you add enough of K from KNO3, that would mean you have to heavily overdose your NO3 which is bad.

Potassium Hydro something.... its KH2PO4.

Mg isn't necessary if you do enough of water change. Add only if your plants are showing deficiency.

I use Lab grade chemicals. So the answer is yes. BUT make sure its not contaminated with other stuff.

[chua]

Thks for all the help.

I also found the Chuck's planted calculator that is pretty helpful.

[Fei Miao]

NO3; from the bloodworms I fed occasionally; PO4; don't see the need in my tank.

[juggler]

[quote:7a0c68ddc7="chua"]Hi juggler,

If i am not mistaken, mg ia also another important element. Do we need to dose that too?

Sorry. A little bit of chemistry here. If KNO3 is added. This mean that it will provide both K and NO3 to the tank. Then for KH2PO4, it will provide PO4 to the tank. What is KH in the chemical name?

What is the chemical name if we want to dose k and mg into the tank. If we add KNO3 to obtain the required k level, we may add excess NO3 into our tank at the same time. Hence, i believe that this chemical is not use for dosing just k.

Lastly, can i use the chemical that is found in the chemistry lab instead of the common Dr Mallick?

Thks for the help juggler.[/quote:7a0c68ddc7]
% of K in KN03 = 39/(39+14+3*16) = 38%
% of K in K2SO4 = 2*39/(2*39+32+4*16) = 44%
% of K in KH2PO4 is not significant.
So KNO3 provides for K as well as NO3.

Mg and Ca are both important. And available in our tap water. Ca proportion has to be more than Mg. So if you dose Mg (using MgSO4), then Ca has to be dosed as well or else you may face problems. Some people don't dose these elements but supply them through frequent water changes. Some people use coral chips in their filter as they provide for both Mg and Ca.

To stick to the topic, you can read the dosing articles in the Aquatic FAQ for more details.

[chua]

Hi

I also found from the calculator that we can also add k using KCL.

But KCL will produce CL as well. Won't it increase the CL level in the tank thus affecting the fish.

Thks again.

[chua]

Thks juggler for the detailed explanation.

You must be very good in your chemistry as you can still remember the molecular mass for the elements.

[juggler]

[quote:5fa409dc21="chua"]Hi

I also found from the calculator that we can also add k using KCL.

But KCL will produce CL as well. Won't it increase the CL level in the tank thus affecting the fish.

Thks again.[/quote:5fa409dc21]

Before I know of Dr Mallick, I used to dose with KCL before. Bought it from NTUC as "Lo-Salt". It has 66% KCL and 33% NaCl. It works as well. But not cheap at about $4.50 per 350g bottle.

The periodic table is available in the internet, no need to remember lah.

[JLudwig]

[quote:fc4e00ecdf="PeterGwee"]15ppm which would be gone in 3-5 days in a high light CO2 tank.), you should need to dose every 2-3 days.[/quote:fc4e00ecdf]

Peter,

I read this everywhere, 2-3ppm a day, I'm almost certain this is a high estimate. I have the following setup:

56L, 2x36W PCF, so 4.8 wpg, I have CO2 set at 50ppm with a pH probe, not a liquid test kit, I supplied every other chemical with N in good excess... I also don't have any fish in the tank, so there is absolutely no NO3 coming from fish waste... this should therefore make my NO3 uptake look higher than others with fish.

The max uptake I've been able to achieve is 6-8ppm a week, which is basically 1ppm a day. I realize I don't have the fastest growing plants, but still, three times my uptake with half of the light and with fish?

Heres what I think the problem/difference might be... I have a VERY good NO3 test kit sold by LaMotte. Using cheaper aquarium kits I always though I was getting 2-3ppm a day, turns out that wasn't true but appear so because of the cheap kit. There are some other possibilities, I may have some toxicity problem in my tank that I don't know about which is holding my plants back for instance... I'm going to redo this experiment with reconstituted RO water to see if this is the case...

I have 10ppm NO3 in my tap so a 50% water change is enough for the week, I think the large water change might be enough for a lot of people, espeically with NO3 in the tap but I'm sure the high end of the estimative index 30ppm is very very high in NO3.

Mr. Amano as far as we know here in the US doesn't add any NO3/PO4 to the water (this is from a message translated a while back, I can post it if anyone is interested but its a little old, we don't have much contact with ADA, you folks in SE Asia might be a little better connected) but he keeps a lot of fish and also uses a substrate fertilizier, this is another technique I'm very eager to explore...

Cheers,
Jeff Ludwig

[PeterGwee]

Jeff, 30ppm is not very high NO3 if you compare what folks in europe are having in their taps plus the fact this max 30ppm of NO3 regime is for very high light tanks with fast growers. A tank with mainly slow growing plants or low light need to dose only 10ppm (max) of NO3 per week. The routine takes into consideration the amount of light, plant load, plant type, NO3 in the tap and critter loading.

Amano's method requires some trial and error with the amount of fishes and that the fact you do see algae in some of his tanks speaks of his methods. I'm not trying to say his method is bad but newbies into the hobby wants healthy looking plants with loads of pearling and not algae. The estimative index method takes away the need for testing except the pH/KH and gives newbies a higher percentage of success in their planted tank route.

If you are still not convince, just write to Tom. I think he will explain it better to you then me.

Regards
Peter Gwee