# Maximum Solubilities and ratios



## chrisl (May 24, 2004)

Is there a website that will calculate the maximum amt of say kno3, kmonoPO4 that'll dissolve completely in X ml's of water? 

Thinking of getting a doser and not sure how much fluid would be necessary to dissolve my 3/4tsp kno3 and 3/16tsp KmonoPO4 given every 2 dys...so that's 3/4 X 3=2.25tsp/wk of kno3 and a little over a 1/2tsp Kmono PO4/wk. So how much fluid am I going to need to keep these suspended in a wks worth of H2O?

Chucks breaks it down by one compound, but not two or more and the solubility issues.

Thanks for any help!
Chris


----------



## Jeff Kropp (Apr 25, 2004)

Chris,

.75 tsp KNO3 with .1875 tsp potassium phosphate mono, if fertilator calculates correctly, is a 3.9 K/P ratio. I have found a ratio of 8.25 K/P works well and the estimative index suggests a ratio of 10 K/P. When I used a 4 K/P ratio I developed problems as I over ran the natural production of N in my tank and induced an N crash.

I would recomend 1/2 tsp KNO3 and 1/16 tsp monobasic P every other day. This will provide a 7.78 K/P ratio and will be easy to measure. If you are calculating for a dosing solution I would recomend an even higher ratio value. My rule of thumb is, that you need a lower ratio of N/P if you feed only dry fish food (8?) and a higher ratio of N/P if you feed live foods (10?). Your mileage may vary...

If fertilator is calculating correctly, I think you could mix 13 tsp KNO3 with 1.5 tsp monobasic P in 500ml water to produce a solution that would provide an N/P ratio of 8.46. In your 75, I think that 20ml every other day of this solution would give good results. 

This macro solution would match well with TMG supplementation, by providing both in equal amounts on alternating days. One day, 20ml macro solution then on the next day, 20 ml TMG. 

This supplementation routine can also be easily adapted to other tank volumes. Just multiply .2667 by tank volume to calculate rough ml volume needed. For example, about 5 ml in a 20g tank.
___
Jeff


----------



## HeyPK (Jan 23, 2004)

I worked out, using densities, the following:
(1) A Saturated solution of MgSO4 is 1.9 molar. Therefore, if you want to dilute a saturated solution to make a 1 molar solution, add 900 mls of water to 1 liter of saturated solution. Or, take any volume of saturated MgSO4 solution and, with water addition, increase it by a factor of 1.9

(2) A saturated KCl solution is 4.1 molar. If you want to make a 1 molar solution of KCl, take 1 liter of saturated KCl and add 3.1 liters of water. Or, take any volume of saturated KCl solution and with water addition, increase that volume by a factor of 4.1. 

(3) A saturated KNO3 solution is 3.7 molar. To make a 1 molar solution, take 1 liter of saturated KNO3 and add 2.7 liters of water. Or, take any volume of saturated KNO3 solution and, with the addition of water, increase the total volume by a factor of 3.7

Saturated solutions were obtained at room temperature, around 23 to 24 degrees Centigrade. 

I like to work with 1 molar solutions, rather than the dry chemicals.


----------



## chrisl (May 24, 2004)

Thanks Alot Jeff and HeyPK for the prompt responses. I'm a little less chemically inclined at this moment LOL I'll give Jeff's suggestions a try as it's easier for me to understand and implement. I had learned of maintaining a 'proper' N/P ratio of about 10, but hadn't yet really thought of getting that specific yet. But you've seen my tank and I'll go with your thoughts. 

I have been wondering though Jeff how much benefit or harm have I been doing to the tank since overdosing on the Equilibrium and HCO3 for last 4wks water changes? Or more to the point....Anything to watch out for now that I'm only replacing the ACTUAL 40ish gal.s instead of 75 w. 1/4tsp/5gal of Equil and HCO3? The new 6.7ph is making the tank pearl alot more already.

Thanks for the help!

I'm learning up on affordable peristaltic pumps for a neat two pump setup and 500mls for ea. Micro&Macro would be great!

Chris


----------



## Jeff Kropp (Apr 25, 2004)

chrisl said:


> The new 6.7ph is making the tank pearl alot more already.


Watch your pearling/streaming to keep an eye on your momentum. You want a nice steady day to day amount, not too much not too little, steady as she goes. Look at your fish in the early morning to see if they seem sluggish which could be one sign of excess CO2. If they seem a little slow back off to pH 6.75ish, then note revised fish ambition and pearling quantities. Make slow changes till you find a sweet spot. Same with macro/micro supplementation, start with proven amounts and watch your pearling/streaming to customize steady day to day amounts for your tank. You shouldn't have to worry about the hardness factors much. Your future water changes will correct any temporary imbalance.
___
Jeff


----------



## HeyPK (Jan 23, 2004)

Also, remember that there are quite a few plant nutrients that only have to be added infrequently. You can expect them to stay in the water and be available to the plants until they are used up by the plants. Of the macronutrients (those used a lot by plants) there would be calcium, magnesium, sulfur and potassium. This leaves nitrogen and phosphorus that have to be added more frequently. Of the micronutrients (only very small amounts needed by plants), it would be all of them except iron and possibly manganese. What does that leave that has to be added more frequently? 
(1) nitrogen in the form of nitrate. It seems to go other places besides into plants. Some gets used by bacteria living where oxygen is low as an oxygen substitute. This process gives off nitrogen gas, N2, which is not available to plants. 
(2) phosphate (PO4). Some of this can precipitate out with iron or with calcium if the pH gets high. 
(3) iron. It is always precipitating out and becoming unavailable to plants. Chelating compounds, such as EDTA, gluconate, DTPA, etc. hold iron atoms in solution and plants are able to extract the iron from the chelating compound. Also, when conditions become anaerobic (no oxygen) in the substrate, insoluble iron compounds become reduced and made soluble and thus accessible by plant roots. Chelating compounds do not last forever. Gluconate has a very short lifetime, EDTA somewhat longer, (a week?), and DTPA lasts for two or three weeks. .


----------



## MarcinB (Apr 16, 2004)

The solubility of KNO3 is 320g/l at 20C. For the KH2PO4 it's 222g/l at 20C.


----------



## chrisl (May 24, 2004)

Thanks again for the replies! I just wanted to tell everyone that the doses Jeff recommended suspended in the 500ml's did indeed get all dissolved. Now it's a bit easier to simply add 20ml's ev. 2dys till i get a doser pump.

Chris


----------



## chrisl (May 24, 2004)

Jeff, my timer only does basically daily functions only; no every other day. So wondering, if giving 20ml''s of my 500ml solution, say gives me 5ppm...can I divide that up and give 10ml every day and still get 5ppms? I dont' think so, but am not sure. 

Thanks for the help. I love my new peristaltic pumps..highly recommended for the memory impaired, like me... or just lazy...like me too heheh


----------



## Laith (Sep 4, 2004)

Chris those pumps sound interesting... (and I love new gadgets!  ).

How are yours set up? do they have their own timer?

Is it true that you can actually have them under the tank (for example) with just the "drip" tube going up into the aquarium?

This would be my main problem with autodosers: I don't have anyplace to put them under the hood.


----------



## IUnknown (Feb 24, 2004)

Laith, The drip tub doesn't even need to go up to the aquarium, it can feed right into the canister tubbing with a tee and a check valve. 
Chris,
Which timer did they give you?
http://www.automatedaquariums.com/dt17c.htm
For example, this one has "98 ON / 98 OFF programming per week"


----------



## gnatster (Mar 6, 2004)

That same timer is $19.95 at Home Depot. Intermatic Model DT 17.


----------



## IUnknown (Feb 24, 2004)

same with the pumps,
http://www.aquaticplantcentral.com/forum/viewtopic.php?t=2250


----------



## Error (Apr 16, 2004)

Despite other recommendations, I think the key to good dosing is to maintain a measurable amount of macronutrients in the water. Your plants will do the rest. There is no set ratio that will work well for your tank. Play with the values until you get good growth. Then mess with dosing pumps once you've established a good regimen.

I believe P is underdosed in most cases. My ratio is about 2:1 or 3:1 NO3/PO4. My plants haven't looked better.

You can play with values for color once everything else is in line.


----------



## chrisl (May 24, 2004)

Laith, yes, the pumps are mounted in a box on the sides, the front of the box I put two outlets, and then ran the elec. plug from inside the box to the front timers in the outlets for electricity. The digital timers are just like IUnknown posted.....and Thanks Greg for pointing that out....I must've been in a brain freeze or something not to see the indiv. days as programmable. 

Good, now I WILL dose 20mls every other day alternating w/ micros.

The question still remains though: If say 20ml's every other day is 'adequate' in stregth, then, using the same solution, but given only 10mls every day....is this the same concentration of macros? I don't think so. Say the 20mls every other day, gives you a NO3 of 5ppms, well then the 10mls would only get you to a level of 2.5ppm per daily dosing if Im not mistaken?? Seems logical, that no matter how often you dose, daily/every other day/whatever, you need to have the nuts AT the required strength of 5ppm of NO3 and 1ppm of PO4. This is what I 'think' is correct??

I was using a ratio of 7.75. .31NO3/.o4PO4, but felt I was a bit NO3 deficient so that's why I wanted to get the ratio a bit higher. 

Thanks for the help guys!

Chris


----------



## Jeff Kropp (Apr 25, 2004)

chrisl said:


> I was using a ratio of 7.75. .31NO3/.o4PO4, but felt I was a bit NO3 deficient so that's why I wanted to get the ratio a bit higher.


Today I did some hand calculations of my .5 tsp KNO3 to .25 tsp enema habit. It yeilded a ratio of 7.166 ppm NO3 to .713 ppm PO4; or roughly a 10/1 N/P ratio. I may try reducing my total N with a 7.5/1 N/P ratio during the next few weeks.
___
Jeff


----------



## IUnknown (Feb 24, 2004)

So when we are trying to achieve plants that are red, we are adjusting the NO3O4 ratio, correct? Compared to using less of both NO3 & PO4. Is the 14.5:1 the min. for growing plants? Or would using a less nitrogen rich ratio bring out the reds? What would that ratio be, 5:1? I mean, there is nothing wrong with using the 10:1 ratio? Maybe we would just get plants that have more red, or would it cause algae problems?


----------



## dennis (Mar 1, 2004)

I think it is time to completely eradicate the low P thinking. Many of us now are finding the higher levels of P, 2-4ppm, don;t cause problems and actually help many plants frow better. It seems to cause more vertical growth and brighter, more intense green colors of plants. What do you give terrestrial plants when you want them to grow strong and bloom? P. It is starting to seem to me, from my very limited experiences and from much reading and assuming from other people's experiences, that there is only one reason to limit P, to slow the plants uptake of N and thus limit growth in general, making tank maintenance easier. P does not cause algae, and actually increasing P usually helps to eliminate spot algae in high light situations.

So, it guess its seems that to bring out the reds, you would keep PO4 the same but lower NO3 levels. This would be a lower ratio correct. Say you switch from 10:2 N (that is a ratio of 8) to 6N:2P (a ratio of 3) That should cause plants like Rotala indica, etc. to produce much redder coloration. this example assume obviously that all other factors, CO2, Trace nutrients, etc, are of appropriate levels.

14.5:1 ratio I do not think is necessary. Plants survive in nature with much less and do fine. They may not look like our tanks buthey certainly survive ad propagate themselves. I think that the levels need to sustain life ar very low, it is the growth that we often strive for in our tanks that are much higher. Maybe someone else could shed more light on this part.

I feel like much of the ratio discussion, exactly how much do you use as opposed to me, is more geared to someone new, or to a new tank. I think it is a way to easily figure out a "safe" range of nutrient levels to get best growth quickly without becoming toxic, making sure no element is limited and basically giving your plants every opportunity for survival, thus limiting algae growth and getting you tank off on the right foot. This is certainly not to say the ratios and nutrient levels are not important to the experienced aquatic gardener, I think they are the ones who figure out the most and help the rest of us.

Will 3:1 ratio grow plants? Will a 20:1 ratio grow plants (obviously, as long as nothing else is limited)? I think the answer to both is yes. I think the questions are really, which is easier to maintain, which suits the individual aquarist best, and their plant species, tank conditions. lighting levels, etc. It seems like anyone can grow plants as long as they give them enough or more of everything, its finding the "sweetspot" that gives optimum growth and expected, desired results that we each are searching for. There are a lot more closet mad scientists out there than are admitted I think I know I am one of them

Together we can help each other find what works best for us, even though someone else may find something different.

And now I am rambling.


----------



## Jeff Kropp (Apr 25, 2004)

dennis said:


> Will 3:1 ratio grow plants? Will a 20:1 ratio grow plants (obviously, as long as nothing else is limited)? I think the answer to both is yes.


Using a ratio is only part of what we do. To discuss only ratios ignores quanities of a ratio and the resulting concentrations of chemicals in solution. If I dose the same ratio solution in different amounts I will get different results. If enough of any given ratio is dosed then ones plants will usually grow. The key point for me is when the supplementation matches the growth rates of my plants. At this point ratios become a more significant factor because they begin to affect N or P limited symptoms.

I must say, that as I push my nutrient concentrations up towards estimative index numbers I have been noticing increased mortality amoung my oldest fishes. From my perspective, this seems to be a significant drawback of running my tank rich in manmade nutrients.
___
Jeff


----------



## Bert H (Mar 2, 2004)

I just want to throw my 2 cents worth into this discussion about ratios of N/P. I have 3 tanks, a 29 gal and 2 tens. All are pressurized CO2 injected (25-30ppm), all around 2.6W/gal. lighting, ages and gravels vary. All are fairly well stocked and the fish well fed daily. Recently I had an eye opening experience. 

My maintenance routine consists of weekly 50% water changes and until about 3 weeks ago I dosed NO3 and PO4 at water changes and midweek. With NO3, I added 10ppm at change and 5ppm midweek. PO4 was added to achieve an 8:1 ratio N/P. I was never happy with the results from cheapie NO3 test kits, and about 3 weeks ago I bought a Hach NO3 test kit, and was shocked when my NO3 in all tanks, measured between 30-40ppm! I didn't have any algae issues, save scraping the glass for some spot algae at change times, plants, for the most part, were growing well, fish appeared healthy. I did a major water change on all tanks to bring NO3 levels down around 10-15. 

Now, I add NO3 to bring level between 10-15ppm at water change time and dosing PO4 to an 5:1 ratio. I am adding PO4 midweek, not NO3. I have measured NO3 every other day in between water changes, and find that it remains basically stable. I can only assume that the food and fish are contributing to this maintenance level. My PO4 kit is a Red Sea and as such, am not sure of its accuracy, but I do find a consumption of PO4 throughout the week, therefore the midweek dosing. Traces and iron are added on other days daily.

So, FWIW, in my limited experience growing plants, I would say, they do have a fairly wide range in which they seem to grow well. I guess it's better to have an excess of everything than limit something.


----------

