Dry vs Diluted ?'s - Fertilizing

Sterling919 · 06-12-2008, 09:24 PM

Can someone explain or point me into the direction of an explanation as to why dry doses yield such higher levels over water mixed ones?

Using Chuck's Calculator (assuming I'm understanding it correctly) if you took 1 teaspoon and mixed it in say 8 ounces of water, you would only need to put about 13ml of the solution into 10 gallons of water to get the desired PPM. That same 1 teaspoon of dry fert just dumped into the tank would jack the PPM out of this world.

Am I understanding it right that mixing it with water dilutes it down? Or am I just not seeing the whole picture and missing something? Is the solution (water mixed) just as strong (8 ounces) as 1 teaspoon of dry mix? Would the PPM level be the same between the two whether watered down first or dry dosed?

The way I'm seeing it right now, it makes more sense to dry dose cause you get higher PPM per dose. But at the same time...I'm thinking that I'm not seeing it straight....

I think you'd get the same PPM results with 1 teaspoon as you'd get with that same teaspoon in 8 ounces of water. The calculator is just saying you'd get a certain PPM by a certain ML if you mixed into a solution instead of dry...have I confused you as much as I've confused myself?

Zapins · 06-13-2008, 12:33 AM

ppm means “part per million,” so if the desired concentration in the tank is 10 ppm that means that there are 10 parts of the chemical to 1 ,000,000 parts of water.

Dry compound is highly concentrated, it is essentially 99 % chemical to 1% water that has condensed out of the air.

If you take 1 gram of dry chemical and add it to 1 liter of water then add the 1 gram to a swimming pool of 100,000 liters your concentration of chemical is much higher in the 1 liter than in the pool since the 1 gram of chemical is much less spread out than it is in the pool.

Now if you take 1 mL from the 1 liter (1,000 mL) that was just mixed with 1 gram of chemical you are basically taking 1/1000th of a gram out. Compare this with taking 1 mL from the pool, which works out to be 1/100,000,000th of a gram of chemical in the 1 mL.

Adding liquid from a pre-mixed bottle of water is much easier and more precise when dosing your tank, because if you only need 1/1000th of a gram of chemical in the tank water how are you going to measure out 1/1000th of a gram of dry chemical without a really expensive scientific scale? It is far easier to get the tiny fraction of a gram of chemical that is required via diluting it down than add dry chemical directly, although if you had an accurate enough scale and good enough tweezers to pick up individual grains of chemical then it would work out to be the exact same thing in both cases.

Adding teaspoons of dry chemical to the tank isn’t usually a good idea, because it usually results in massively overdosing the tank with chemical (to the point of toxicity).

ray-the-pilot · 06-13-2008, 04:50 AM

If you put 1 teaspoon full of a chemical in your tank, you put 1 teaspoon in your tank (that's easy).
If you put 1 teaspoon of a chemical into 500ml of water (this is about 100 teaspoons) then take one teaspoon of this solution and add it to your tank you've add:
1/100 x 1 teaspoon of the chemical. i.e. 0.01 teaspoons.
The remaining .99 teaspoons are still in the solution that you didn't use.

hoppycalif · 06-13-2008, 09:03 AM

Quote:

Originally Posted by ray-the-pilot

If you put 1 teaspoon full of a chemical in your tank, you put 1 teaspoon in your tank (that's easy).
If you put 1 teaspoon of a chemical into 500ml of water (this is about 100 teaspoons) then take one teaspoon of this solution and add it to your tank you've add:
1/100 x 1 teaspoon of the chemical. i.e. 0.01 teaspoons.
The remaining .99 teaspoons are still in the solution that you didn't use.

A wise person then saves that .99 teaspoons in that solution, and uses it to dose the tank, one teaspoon at a time, until the mixture is used up, 99 doses later. Or, you can just dump the bottle and start over each day.

Sterling919 · 06-13-2008, 09:28 AM

And doing that would make me an idiot...haha...and my ferts would be wasted quickly.

I figured it like you guys said it but I just wasn't thinking last night as late as it was.

Zapins · 06-13-2008, 10:59 AM

It is ok to ask questions if you are unsure, even a little. Better to confirm than keep wondering or worse - do something wrong and have a disaster on your hands.

Sterling919 · 06-15-2008, 02:40 PM

Well what I'm going to do is focus on my 40g breeder tank as my main planted tank. The 10g I have just seems to be to "iffy" and hard to deal with...especially for a newbie like me. I've not had a big amount of luck with that tank.

I'm trying to use Chuck's Calculator to figure how to dilute the ferts I got into something I can use in my tank without frying them and the fish. I don't exactly understand the workings of this even though it seems very simple and I feel like an idiot for not being able to get this. First off for the sake of this thread here is what I bought :

Potassium Nitrate - 1lb
Mono Potassium Phosphate - 1lb
CSM+B Plantex - 1lb

All came from AquariumFertilizer.com (which ships super fast). What I'd really like to know is how to combine these three into one diluted mix and use the PMDD method of 1 drop per gallon everyday. I also have a bottle of SeaChem Flourish but I'm thinking the Plantex is the same thing and maybe contains what Flourish lacks...I don't know.

Now using Chuck's calculator I see two different solutions for the Potassium Nitrate. Both call for different target levels so how can you dose the same chemical for two different PPM target levels without raising the level of the lower PPM target level? That is one thing that confuses me and has had me scratching my head. Next on the mono potassium phosphate bag it gives directions to make this mix but it seems a rather large amount to keep stored. My frig is kinda full and my wife is a constant complainer who gripes about my hobby when she can...almost all the time lately. And then I don't think I've seen anything about dosing the Plantex.

Now I have seen the estimated dosing chart but I really like the idea of just dosing enough or less and doing it everyday...hence the PMDD. I'm new to this and haven't learned all the abbreviations and such for the chemicals yet. I've pretty much got the KNO3...atleast it's a start, right?

Is there a way to combine those three ferts that I've got and then use the PMDD method to dose them? Or is there a method to combine the KNO3 and the mono potassium phosphate and just use the Flourish with the PMDD method until it's all gone so that I've not wasted my money in it?

Any help or suggestions?

hoppycalif · 06-15-2008, 07:57 PM

You can combine the macro fertilizers, KNO3 and KH2PO4, into one liquid mix, but you can't add an iron containing micro fertilizer mix into that same bottle. That causes the iron to be precipitated out as an insoluble substance that just settles to the bottom of the bottle.

To get to one drop per gallon as the dosage takes some calculations, assuming you don't want to just use the PPS Pro method, which is almost what you are describing. And, Flourish is a good trace mix to use instead of CSM+B, although I seem to recall being told there is no iron or too little iron in it.

Sterling919 · 06-15-2008, 09:13 PM

Well that is what I'd like to do, combine the KNO3 and KH2PO4 together into one solution and use the PMDD method. Which I believe is 1 drop per gallon of aquarium water per day. I don't mind the estimated dosage method but I'm kinda lazy sometimes and don't want to do a 50% water change every week. Thinking about it...that probably isn't a bad idea...changing 50% of the water every week. Since a 20% water change would be about 10 gallons...in a 40g tank I guess we're only talking about changing double the amount of water.

But at the same time...it seems like a waste of ferts to dose that much and then dump it out in a week. The dry ferts don't cost that much and from what I understand 1lb bags should last about 1yr even doing it this way. But at the same time I feel like that the PMDD is a better way which results in less product being "wasted" and a better way insure that you aren't over dosing the tank.

I believe that the Flourish contains a low amount of iron and could be part of my problem with some of my plants...not enough iron in the water. I guess I'll have to research that and see what I come up and then run my thoughts by you guys and see what you think.

AquariumFertilizer.com offers a PMDD mix and I believe it contains the CSM+B mix too. So if I'm right are you saying it's a bad deal because of the iron? The KNO3 and KH2PO4 is what I have along the lines of macro ferts...should I have something else too? If I need something else, then from what they've got, what do I need to order? And then does anyone know how to mix them so I can follow the PMDD method?

Or am I wrong all the way around and should I just go by the estimated dosing method? And then from what I get by using Chuck's calculator...the methods of estimated dosing put you over the PPM limit or target range for your tanks volume. KH2PO4 for example... .25 teaspoon...1/4 of this dry will put you over the target level of 1 PPM. So if you do that 3 times a week...you are really over the limit by the end of the week. Isn't that bad? And if so, then wouldn't the PMDD be better?

Dry ferts are cheaper. I like being able to feel that 1lb and seeing that bag full of fert over that 4 or 8oz bottle of SeaChem stuff. Makes me feel like I'm getting more for my money. But the liquid stuff by SeaChem seems so much easier to dose and use than trying to do it by dry ferts.

hoppycalif · 06-16-2008, 09:39 AM

PMDD did not contain any significant amount of phosphates. When that method was devised it was believed that phosphates were the cause of algae growth. Only later was it determined that plants need phosphates, too.

Have you looked at the Pfertz liquid fertilizers - costing a lot less than Seachem's but more than dry chemicals? They are dosed by the squirt, as I recall.