Easier macro dosing

[Wasserpest]

Pondering some solutions for easier macro dosing... The water pump dosing works great, but still, trying to simplify things further...

Has anyone ever thought of using a little (maybe clear plastic) container, filled with say a weekly dose of macros and water, placed into the tank, with a little hole (maybe adjustable opening) through which the higher concentrated solution will diffuse into the tank, over the period of a week or two or whatever?

Possible downfalls of that...

Adjustment - could be dependent on surrounding water circulation, that is, in an area of higher current the nutrients would get sucked out of the container quicker.

Different solubility of chemicals - maybe KH2PO4 dissolves much easier than K2SO4, so you would have spikes of different nutrients throughout the dosing period?

Maybe one could use glass tubes, like used for testing, fill them up with the powder, and use a stopper with a hole, and watch the powder disappear over time... hmmmm... gotta play with that...

[darkfury18]

hrmm... interesting

[Wasserpest]

Yeah, interesting.

Spypet, why did you post a picture of the Aquadose container? That isn't really new, is it? And has nothing to do with what I am talking about.

I am talking about a little test tube or something similar.

[dougiefresh]

Good idea. This is similiar to how they dose chlorine/bromine in hot tubs. A simple plastic container that floats around and under it and you can dial in your dosage by number of holes.

[Hoppy]

If you dissolve the ferts in water, and use that in the "leaky" container for dosing, the incoming water will dilute the remaining water in the container, so the dosage per day will steadily drop asymptotically to zero. If you use solid ferts in the bottle.......????

If you put a rubber bladder inside the rigid bottle, with slightly pressurized air between the bladder and the inside of the bottle, the liquid ferts might be expelled at a near constant rate. And, if I were the son of Warren Buffett (in good standing) I could afford to use all ADA equipment.

[Wasserpest]

What I was thinking was not to dissolve them (they won't, it's too much salt and not enough water), but to just let them settle down on the bottom of the vial. Therefore, you would have a near saturated solution in the container, which is just slowly diluted by tank water.

I imagine you could use bigger vials for KNO3 and K2SO4, and thinner ones for KH2PO4. Say you use 5 tsp of KNO3 for 2 weeks of dosing, you'd fill a thicker glass half of that, fill with water, let it settle, plug it shut and attach with rubber sucker in tank. Say you use 1/2 tsp of KH2PO4, you find a really thin vial, and do the same. Size of the diffusion hole would be the main regulation mechanism.

[g8wayg8r]

Is this the general idea?

Get a ketchup bottle with the witch-hat cap; drill a small hole in the bottom; fill it with your solution; invert it where the tip of bottle is in a stream from your spray bar; low pressure sucks out small amounts of your solution continuously. If it is, you could alway get a bottle with and rubber tube that has a nipple on the end (like the needle used to fill basketballs, etc). That could give you more flexabiltiy in mounting location.

[Wasserpest]

Not quite... I am hoping that the concentrated solution dilutes in the surrounding water passively, without any help from spraybars.

Here is what I did last night, to get the testing started. I used two 3ml oral syringes, and one 0.5ml syringe. (With the markings on the syringe it is easier to keep track of changes).

I put 1/4 tsp of KNO3 in one and 1/4 tsp of K2SO4 into the other large syringe. That filled about 1.5 ml, then I added water which reduced the salt to 1 ml.

So now I have two syringes filled with 1 ml powder and 1 ml water. Similar for the smaller syringe which contains (less) KH2PO4 powder.

I placed all 3 syringes in my tank, with the opening pointing up. Now it is sitting back and monitoring how fast the fertilizer gets distributed into the water.

This morning (8 hours later) I did not notice any difference yet. The holes in the oral syringes are relatively large... perhaps this needs to be moved to an area of higher current if it doesn't dissolve fast enough.

I think this idea is mind-boggling in its simplicity. No ketchup or gallon bottles on top of the tank, just a (few) good looking glass vials with the powder and some water, small, easy to hide, still easy to check on...

[g8wayg8r]

Although this isn't as simple as an open vial, I wonder if you could use an airstone, some tubing and your container of concentrate. Let the head slowly push the concentrate through the airstone or just saturate the airstone. If you have any water movement, that should be sufficient to dose the tank. Plus, small internal filters are inexpensive and could be used as well to help out if your water is somewhat stagnent. If your aquarium is 18" (457 mm) tall and your container is a quarter of that, you won't get that much of difference in head so the dosing shouldn't vary that much.

[Hoppy]

Originally Posted by Wasserpest

What I was thinking was not to dissolve them (they won't, it's too much salt and not enough water), but to just let them settle down on the bottom of the vial. Therefore, you would have a near saturated solution in the container, which is just slowly diluted by tank water.

I imagine you could use bigger vials for KNO3 and K2SO4, and thinner ones for KH2PO4. Say you use 5 tsp of KNO3 for 2 weeks of dosing, you'd fill a thicker glass half of that, fill with water, let it settle, plug it shut and attach with rubber sucker in tank. Say you use 1/2 tsp of KH2PO4, you find a really thin vial, and do the same. Size of the diffusion hole would be the main regulation mechanism.

Now this sounds very workable! When the vial shows no solids in it would be the time to replenish it. One possible problem, which may account for what you saw after one day: water with varying amounts of salts in it will stratify and be pretty stable. I think there needs to be some slight stirring going on, or I'm not sure if there would be any diffusion going on at all. At least this is easily testable, as you are doing. A person with a fresh mind for doing the calculations necessary should be able to find out theoretically how fast the "salty" water would diffuse out.

[Wasserpest]

I think placing it in an area of gentle water current, then adjusting the size of the opening will work great. Obviously the opening in the syringe is a little on the small side, of course much depends on the size of the tank that is to be dosed.

Last night I took it up a notch. Used two 12ml measuring tubes (they come with Red Sea Nitrate/Phosphate tests), attached them to a rubber sucker, filled them with one tsp KNO3 and K2SO4 respectively, and put them into the tank. This morning I noticed a slight reduction... not sure if it dissolves or compacted some over night. I think this might just work great...

BTW one tsp of powder translates into about 4ml of volume in the test tube. So the 12ml tubes would hold ~3 tsp, enough for 2 weeks of N or 3 weeks of K for my 100gal tank.

The neat thing is that this can be fairly small, and unobtrusive... made all out of glass, you won't notice much. Just put it in a place where you can observe the level of salt.

[Wasserpest]

Originally Posted by g8wayg8r

Although this isn't as simple as an open vial, I wonder if you could use an airstone, some tubing and your container of concentrate. Let the head slowly push the concentrate through the airstone or just saturate the airstone. If you have any water movement, that should be sufficient to dose the tank. Plus, small internal filters are inexpensive and could be used as well to help out if your water is somewhat stagnent. If your aquarium is 18" (457 mm) tall and your container is a quarter of that, you won't get that much of difference in head so the dosing shouldn't vary that much.

I think I understand what you are suggesting, but what I like most about what I am trying to do is the simplicity... nothing to install on top of the tank, no airlines, pumps, things that can clog up quickly... just a partially covered vial, filled with salt. Plus, very easy to see if it is still dosing, or about to run out.

I will post some pics soon, maybe that will help to demonstrate the very simple concept.

[tazcrash69]

Wasser, please correct me if I'm way off base.
It almost sounds like an adaptation of the miracle grow fertilizer my wife uses on her flower garden. Instead of a hose providing the water it would be flow from the filter output.

If it's not,
Sorry it's the closest adaptation to what I think you are describing that I can think of in the real world.

EDIT:
Sorry just read this:

Originally Posted by Wasserpest

Not quite... I am hoping that the concentrated solution dilutes in the surrounding water passively, without any help from spraybars.

Guess I'm off.

[Wasserpest]

I think that describes it well enough... with the fertilizer bottle and water hose, there is a hose going down into the solution, and the stream of water through the garden hose creates some vacuum and sucks the fertilizer out of the bottle. This here is very similar actually.

I promise I'll post some pictures by the weekend... just want to work out the first obvious bugs.

[g8wayg8r]

Got it. Think about this. If you are dissatisfied with the rate of solution when the vial is upright, why not turn it on it's side to some degree so the density difference of the fertilizer solution and aquarium water gives you a gradient to allow the concentrate to flow more readily. That way, you aren't relying just on the water motion to draw the solution out of the vial. You could also use a plastic vial and insert a tube through the bottom and extend it maybe a cm or so. As the concentrate reaches the top of the tube, the density difference allows it to flow down into the tank.