Advice for fertilizer schedule

[Supermassive]

@Mmiller2001 @JoeQ If I was going to dry dose KH2PO4 how would I do that in a 10 gallon tank since I need such a tiny amount? Add some to distilled water and use that as a sort of liquid fert? Or is there a better liquid phosphorous I could use instead of flourish?

[JoeQ]

On 1/20/2024 at 11:24 AM, Supermassive said:

@Mmiller2001 @JoeQ If I was going to dry dose KH2PO4 how would I do that in a 10 gallon tank since I need such a tiny amount? Add some to distilled water and use that as a sort of liquid fert? Or is there a better liquid phosphorous I could use instead of flourish?

For dry dosing that small of a tank I wouldn't even bother, its too much trouble! You would have to messure out 0.07g (of Kh2po4) with each dose. With that small of an amount Id instead make a solution which you messure out per milliliters or pumps. Its probably best to use what you have for now. 

Edited January 20 by JoeQ

[Mmiller2001]

Making a solution would work. What amount of teaspoons is it saying?

[Supermassive]

On 1/20/2024 at 12:07 PM, Mmiller2001 said:

Making a solution would work. What amount of teaspoons is it saying?

Its saying less than 1/64. Its about 55 milligrams K2HPO4 for 1ppm PO4 in my tank.

[Mmiller2001]

On 1/20/2024 at 10:14 AM, Supermassive said:

It’s saying less than 1/64. It’s about 55 milligrams K2HPO4 for 1ppm PO4 in my tank.

I hate making solutions but that’s the way to go. Just make it dilute. Say 10ml of solution for the amount you want to dose. I bought a gram scale with 100ths calibration for small amounts as this.

[Supermassive]

On 1/20/2024 at 12:17 PM, Mmiller2001 said:

I hate making solutions but that’s the way to go. Just make it dilute. Say 10ml of solution for the amount you want to dose. I bought a gram scale with 100ths calibration for small amounts as this.

I have a scale but it only goes to tenths I believe. I could make a mixture but it would have to a bit more concentrated to get a precise measurement or I could make a large volume like 1 liter but I think it would be easier with a smaller container and a smaller more concentrated dose. I've never done this before so is there anything I need to know? Do you just mix it with distilled water and it will last forever?

I'll keep using the flourish until I run out and then ill look into some dry options.

[JoeQ]

Make small batches when you start out until you find a recipe you like. I ended up throwing more out than I care to admit on account of not liking the fertilizer, solubility issues, wrong calculations, I wanted to try a different mix or simply I needed an extra bottle.....

Also use, pure, distilled or RO water. I like to buy the pre messured drinking bottles, its one less thing to messure and can also be easily warmed beforehand via a waterbath or leaving it in a warm car which helps with solubility. Just don't open it till you are ready to mix else you mess up your calculations.

Finally make it a few days before you need it. Again its just a matter of giving your solution enough time to desolve

[JoeQ]

Lastly store your solutions in a cool dark place to avoid mold growth

[Supermassive]

On 1/20/2024 at 3:30 PM, JoeQ said:

Lastly store your solutions in a cool dark place to avoid mold growth

Should this also be done if you premix water 

[JoeQ]

On 1/20/2024 at 3:38 PM, Supermassive said:

Should this also be done if you premix water 

The solutions you make yourself with distilled water is what im referring to. I don't believe this is an issue with store bought pre mixes 

[Supermassive]

On 1/20/2024 at 3:40 PM, JoeQ said:

The solutions you make yourself with distilled water is what im referring to. I don't believe this is an issue with store bought pre mixes

I get that. What I meant was if you mix tap water and RO or distilled water should that be stored in a cool dark place

[JoeQ]

On 1/20/2024 at 3:46 PM, Supermassive said:

I get that. What I meant was if you mix tap water and RO or distilled water should that be stored in a cool dark place

I have no answer for that. I can't picture tap and RO being stored long term

[Seattle_Aquarist]

On 1/19/2024 at 10:57 AM, Supermassive said:

Will do, thanks. If you don't mind could you please explain why only the PO4 matters if its not too complicated

Hi @Supermassive,

 

Thank you @Mmiller2001 for the shout out.  Phosphorus (P) is an element that is always found in nature bonded to other elements or chemicals (two common examples are ammonium or potassium) and never found as pure phosphorus (P).  Plants uptake phosphorus through the roots only in the form of orthophosphates (or phosphate joined to other chemicals or elements like in the examples).  I cannot answer why Rotala Butterfly states that there is P "left over" after dosing KH2PO4 since any P that resulted would bond with another chemical or element in the tank to form an orthophosphate.  -Roy

[Supermassive]

On 1/21/2024 at 11:09 AM, Seattle_Aquarist said:

Phosphorus (P) is an element that is always found in nature bonded to other elements or chemicals (two common examples are ammonium or potassium) and never found as pure phosphorus (P).  Plants uptake phosphorus through the roots only in the form of orthophosphates (or phosphate joined to other chemicals or elements like in the examples).  I cannot answer why Rotala Butterfly states that there is P "left over" after dosing KH2PO4 since any P that resulted would bond with another chemical or element in the tank to form an orthophosphate.  -Roy

Ah okay I didn't know that. That is interesting.

Are all orthophosphates treated the same by plants or do they absorb PO4 the best? I still don't get why you only account for PO4 and not P2O5.

On 1/21/2024 at 11:09 AM, Seattle_Aquarist said:

I cannot answer why Rotala Butterfly states that there is P "left over" after dosing KH2PO4 since any P that resulted would bond with another chemical or element in the tank to form an orthophosphate.

Maybe they cant predict what compound it will form so they just leave it as P.

[Seattle_Aquarist]

On 1/21/2024 at 8:26 AM, Supermassive said:

Ah okay I didn't know that. That is interesting.

Are all orthophosphates treated the same by plants or do they absorb PO4 the best? I still don't get why you only account for PO4 and not P2O5.

Maybe they cant predict what compound it will form so they just leave it as P.

Hi @Supermassive,

P2O5, or Phosphorus pentoxide, is a crystalline powder.  It is very soluble with a 90% - 95% solubility.   When added to water it creates H3PO4 which is an orthophosphate.  As an orthophosphate becomes available for plants to uptake. -Roy

[Supermassive]

@Mmiller2001  If I do mix my own phosphorous solution what ppm would you recommend for a target in my tank?

[Mmiller2001]

On 1/22/2024 at 3:20 PM, Supermassive said:

@Mmiller2001  If I do mix my own phosphorous solution what ppm would you recommend for a target in my tank?

Using CO2?

[Supermassive]

@Mmiller2001 No CO2

[Mmiller2001]

On 1/22/2024 at 3:49 PM, Supermassive said:

@Mmiller2001 No CO2

Then I would start at 2ppm and maybe up to 4ppm if need be.

[Mmiller2001]

On 1/20/2024 at 1:46 PM, Supermassive said:

I get that. What I meant was if you mix tap water and RO or distilled water should that be stored in a cool dark place

Only use distilled water when mixing nutrients.  Macro solutions can just be placed in a dark area. You can also add about 1ml of Glut to the mix if you are worried about mold.

Edited January 23 by Mmiller2001

[Supermassive]

There is a lot of detritus from decayed catappa leaves on the surface of my gravel. I syphoned a lot of it out on WC day. Ill keep working on that when I do weekly WCs. I also read/heard that its bad to have fluctuating CO2 levels so I'm going to start letting my water sit for a few days before WCs. I estimated my tap water has 10-20ppm CO2 in it. I thought that was good for my plants but it seems like its actually working against me from what I've learned.

There also seems to be 4 or more types of algae going on that I can see. A green dust or carpet algae coating a lot of leaves. Green dust algae on the glass. GSA also on some leaves but not nearly as many as the carpet algae. A green filamentous algae. I don't think its hair algae. Its very fine threads and they are short, less than 10mm. Also not on nearly as many leaves as the carpet algae and there's some on the glass too. And lastly some sort of brown or black algae. Its an extremely thin layer like its painted on. I'm not sure if that's a type of diatom. I've read/heard some of those types of algae are typical in a new tank and will go away with water changes and as the tank gets more mature but the tank has been setup since September-October so yeah I'm not sure what to think. Is that process much slower in a non CO2 tank?

Another thing I'm seeing is pinholes. Mostly on the S. Repens but a little bit on the Java fern and Hygrophila too. I know that's supposed to be potassium deficiency but I also know it could be other things. I've had my potassium tested before and it was ~20ppm. I know you can run potassium quite high with no issues but I thought 20ppm was sufficient. I get almost all of my potassium from EG and I just assumed if my nitrates are good then potassium is too but maybe I'm wrong. I have flourish potassium so it probably wouldn't hurt to add some.

So far the only real changes I've done is added a lot more phosphorous and trying to keep the gravel surface a lot cleaner. I've been adding 1ml Flourish phosphorous every day which is ~0.13ppm PO4. That should put me around 2ppm over time but I am going to get some potassium phosphate and make a solution and switch when I run out of the flourish.

I'm also dosing flourish comprehensive and iron twice a week now and splitting my EG dosing into a half dose twice a week but maybe I should just stick with extra PO4 for now. I know your not supposed to make a bunch of changes at once.

[jo1414]

One thing no one has mentioned is that you wrote you don't use root tabs. The issue is both of those plants are heavy root feeders. They need root tabs. Once you get those growing a little better the algae problem should fade away. (Unless there is something else going on.) The S. Repens does pull from the water column but needs more. Adding root tabs and water column fertilizer may solve all your problems and you wouldn't need to venture into the addition of PO4 and CO2. But there is a lot of good advice about that in the post.

[Supermassive]

On 1/26/2024 at 4:24 PM, jo1414 said:

One thing no one has mentioned is that you wrote you don't use root tabs. The issue is both of those plants are heavy root feeders. They need root tabs. Once you get those growing a little better the algae problem should fade away. (Unless there is something else going on.) The S. Repens does pull from the water column but needs more. Adding root tabs and water column fertilizer may solve all your problems and you wouldn't need to venture into the addition of PO4 and CO2. But there is a lot of good advice about that in the post.

Yeah Its probably worth a try. I have enough flourish phosphorus to last about a month so if I see no results in the next 2-3 weeks ill put in some root tabs and see what happens after another few weeks.

Thanks for the suggestion.

[Supermassive]

@Mmiller2001  From what I'm reading on the Non CO2 methods Barr Report it seems like it would be beneficial to have root tabs or some sort of nutrients in the substrate. He says "Set up the substrate well, this is the main part of the non CO2 tank." He also mentions it a few other times. Have you done water column only fertilization with low light and no CO2?

 

 

Edited January 27 by Supermassive

[Mmiller2001]

On 1/26/2024 at 9:32 PM, Supermassive said:

@Mmiller2001  From what I'm reading on the Non CO2 methods Barr Report it seems like it would be beneficial to have root tabs or some sort of nutrients in the substrate. He says "Set up the substrate well, this is the main part of the non CO2 tank." He also mentions it a few other times. Have you done water column fertilization only with low light and no CO2?

 

 

I do and I haven’t found a reason to use them in either scenario.