Scaling EI down for a 5.5 gallon tank - The Planted Tank Forum
Old 06-06-2006, 05:03 PM Thread Starter
Planted Tank Obsessed

Join Date: Oct 2005
Location: Bunker Hill, WV
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Scaling EI down for a 5.5 gallon tank

Using the sticky dosing amounts for 20 gallon / 4 + Chucks calculator + windows calculator I get this:

KNO3 - .0625 tsp 3x week = ~11 ppm nitrate = ~7 ppm potassium each dose
KH2PO4 - .015625 tsp 3x week = ~3.6 ppm Phosphate each dose
K2SO4 - .015625 tsp 3x week = ~2.4 ppm Potassium each dose
Trace - 1.25 ml 3x week (250 ml water + 1 tbspoon CSM+B or Commercial trace mix)
Iron - .375 ml 3x week (commercial Iron mix)

since one would be hard pressed to find .15 tsp measuring spoons, and not everyone has a digital scale, I've converted this to an easy pre-mix:

Macro Formula
250 ml. Water
3.00 teaspoons KNO3 (2.1 ppm Nitrate and 1.3 ppm Potassium per ml.)
2.00 teaspoons K2SO4 (1.13 ppm Potassium per ml.)
0.75 teaspoons KH2PO4 (.53 ppm Phosphate per ml.)

5 ml 3x weekly should be ~ the same as the dry dosing

My schedule for a 5.5 gallon high light (two 1x13 AH bright kits):
Sunday - 5 ml. macro solution
Monday - 1.25 ml trace, .5 ml iron
Tuesday - 5 ml. macro
Wednesday - 1.25 ml. trace, .5 ml iron, 1 ml. Flourish Trace*
Thursday - 5 ml. macro solution
Friday - 1.25 ml. trace, .5 ml. iron
Saturday - 50% water change, prune and trim, clean glass, etc...
* Flourish Trace is being used as this is 100% un-reconstituted RO/DI water

I started this today (Tuesday 6/6/06) and will see how it works out for several weeks. Eventually I plan to lower my KNO3 to bring out some color in R. wallachi, but would rather start closer to a known working schedule.

Input? Confirmation? Argument?

Edit: Typo...Second Edit: Fixed formula miscalc.

Last edited by gbhil; 06-06-2006 at 07:33 PM.
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Old 06-06-2006, 05:55 PM
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Quote:
Originally Posted by gbhil
Using the sticky dosing amounts for 20 gallon / 4 + Chucks calculator + windows calculator I get this:

KNO3 - .0625 tsp 3x week = ~11 ppm nitrite = ~7 ppm potassium each dose
KH2PO4 - .015625 tsp 3x week = ~3.6 ppm Phosphate each dose
K2SO4 - .015625 tsp 3x week = ~2.4 ppm Potassium each dose
Trace - 1.25 ml 3x week (250 ml water + 1 tbspoon CSM+B or Commercial trace mix)
Iron - .375 ml 3x week (commercial Iron mix)
I'm assuming you meant 11 ppm *nitrAte*

All these numbers look good. There is a slight variation depending on which calculator is used but all differences I found were extremely small and your results are consistent. Math looks good.

Note that the KH2PO4 also adds about 1.33 ppm K, probably increase that to 1.4 ppm or so because Chuck's calc outputs slightly higher readings than the one I happened to be using. Just mentioning this because you listed the K levels of KNO3 but not KH2PO4.

Quote:
Originally Posted by gbhil
Since one would be hard pressed to find .15 tsp measuring spoons, and not everyone has a digital scale, I've converted this to an easy pre-mix:

Macro Formula
250 ml. Water
3.00 teaspoons KNO3 (2.1 ppm Nitrate and 1.3 ppm Potassium per ml.)
1.25 teaspoons K2SO4 (1.2 ppm Potassium per ml.)
0.75 teaspoons KH2PO4 (.53 ppm Phosphate per ml.)

5 ml 3x weekly should be ~ the same as the dry dosing
I downloaded Chuck's calc for this section and everything looks correct except for your K2SO4 readings. According to Chucks's calc adding 1.25 tsp K2SO4 to 250 ml H20 will yield 0.71 ppm K per ml.

2.11 tsp K2SO4 in 250ml H20 was needed to receive a reading of 1.2 ppm K per ml so you may want to double check that.

"Insanity: doing [or asking] the same thing over and over again and expecting different results."
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Old 06-06-2006, 06:11 PM
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Join Date: Jun 2005
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Quote:
Originally Posted by gbhil

My schedule for a 5.5 gallon high light (two 1x13 AH bright kits):
Sunday - 5 ml. macro solution
Monday - 1.25 ml trace, .5 ml iron
Tuesday - 5 ml. macro
Wednesday - 1.25 ml. trace, .5 ml iron, 1 ml. Flourish Trace*
Thursday - 5 ml. macro solution
Friday - 1.25 ml. trace, .5 ml. iron
Saturday - 50% water change, prune and trim, clean glass, etc...
Also, dosing 5ml of the KH2PO4 solution will add 2.65 ppm PO4, slightly short of the 3.6 ppm that was mentioned in the dry dosing schedule. If you were to add an extra 1/8 tsp of KH2PO4 to your macro formula that would increase it from .53 ppm to .875 which would increase the PO4 level in 1ml of the solution up from .53 ppm PO4 to almost .62. Multiply that by 5 and your new 5ml dose would add about 3.1 ppm, getting you much closer to the 3.6 ppm mentioned in the dry dosing without making the dry chemical measuring any more complicated, assuming you have a 1/8 tsp to measure with.

Another consideration. You mentioned that this 5.5g tank is lit by 2 x 13w AH Bright Kits. You did not mentioned Deluxe. Without the AH reflectors I'm not sure this tank qualifies as high light. For example, I have 2 x 13w over a 2.5g tank that gets daily Excel for organic carbon supply and I dose this tank with a standard Ei schedule at 50% normal levels. You are talking about dosing a 5.5g with roughly the same amount of light using the same dosing schedule I use but you are going to be dosing twice the ppm levels. I'm not sure the light level you have requires full blast Ei dosing levels. Are you running Co2 or Excel or any form of Carbon enrichment?

Assuming you make the correction with the K2SO4 you will have successfully scaled down Ei for your tank volume but you can also scale Ei down to lighting intensity as well. Tom developed your original Ei target levels in a very high light tank with very fast growers and with high Co2 levels. If you aren't running Co2 and aren't running high light, you may be able to cut the ppm target levels in half since your plant uptake rates will be much lower.

Ei was designed with no limiting factors in mind, lower light and lack of co2 are limiting factors.

You can continue dosing like you are and watch what happens. If it causes you no problems then it isn't a problem. Ei was designed with a "controlled level of overdose" in mind anyway. Just wanted you to be aware you might be overdosing by twice the needed amount. You can try cutting your dosage down to 2.5ml daily if you're using a graduated dropper. If you are using a cap or whatever to dose you could always measure the volume of liquid you have remaining and then add that volume of water to it to do a 50% dilution and then just keeping the usual 5ml amounts.

Just suggestions. Like I said, if it works, it ain't broke. Just realize that if you start having problems your dosage levels might need to be considered in identifing the cause.

"Insanity: doing [or asking] the same thing over and over again and expecting different results."
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Old 06-06-2006, 07:12 PM Thread Starter
Planted Tank Obsessed

Join Date: Oct 2005
Location: Bunker Hill, WV
Posts: 344
Quote:
I'm assuming you meant 11 ppm *nitrAte*

All these numbers look good. There is a slight variation depending on which calculator is used but all differences I found were extremely small and your results are consistent. Math looks good.

Note that the KH2PO4 also adds about 1.33 ppm K, probably increase that to 1.4 ppm or so because Chuck's calc outputs slightly higher readings than the one I happened to be using. Just mentioning this because you listed the K levels of KNO3 but not KH2PO4.
yeah, meant nitrate...thanks for pointing that out, corrected.

I was under the impression (likely the wrong one) that the K in KH2PO4 was chemically bound in a way inaccessable to plants. No reference where I got this info, just one of those tidbits you tend to remember. From this point on, I'm going to consider that as bad information, unless someone steps up and confirms it.

Quote:
I downloaded Chuck's calc for this section and everything looks correct except for your K2SO4 readings. According to Chucks's calc adding 1.25 tsp K2SO4 to 250 ml H20 will yield 0.71 ppm K per ml.

2.11 tsp K2SO4 in 250ml H20 was needed to receive a reading of 1.2 ppm K per ml so you may want to double check that.
Thats the kind of feedback I wanted. Thanks for double checking my double checking. Will adjust my mixture to 2 tsp. to get 1.13 ppm/ml.

Quote:
Another consideration. You mentioned that this 5.5g tank is lit by 2 x 13w AH Bright Kits. You did not mentioned Deluxe. Without the AH reflectors I'm not sure this tank qualifies as high light. For example, I have 2 x 13w over a 2.5g tank that gets daily Excel for organic carbon supply and I dose this tank with a standard Ei schedule at 50% normal levels. You are talking about dosing a 5.5g with roughly the same amount of light using the same dosing schedule I use but you are going to be dosing twice the ppm levels. I'm not sure the light level you have requires full blast Ei dosing levels. Are you running Co2 or Excel or any form of Carbon enrichment?
I'm using AH reflectors, and the enclosure is completely lined with mylar. Lights sit about 2.5 inches above surface.
Using a hagen ladder with champange yeast for 3 bubbles/2 seconds ATM. Have an aluminum manifold with clippard valves being built and neoprene tubing on order. 87 pound tank in the garage already running one high light EI tank. (converted argon tank from a welding cart) Hopefully the industrial neoprene tubing will work for this 28' run.

Quote:
Assuming you make the correction with the K2SO4 you will have successfully scaled down Ei for your tank volume but you can also scale Ei down to lighting intensity as well. Tom developed your original Ei target levels in a very high light tank with very fast growers and with high Co2 levels. If you aren't running Co2 and aren't running high light, you may be able to cut the ppm target levels in half since your plant uptake rates will be much lower.

Ei was designed with no limiting factors in mind, lower light and lack of co2 are limiting factors.

You can continue dosing like you are and watch what happens. If it causes you no problems then it isn't a problem. Ei was designed with a "controlled level of overdose" in mind anyway. Just wanted you to be aware you might be overdosing by twice the needed amount. You can try cutting your dosage down to 2.5ml daily if you're using a graduated dropper. If you are using a cap or whatever to dose you could always measure the volume of liquid you have remaining and then add that volume of water to it to do a 50% dilution and then just keeping the usual 5ml amounts.

Just suggestions. Like I said, if it works, it ain't broke. Just realize that if you start having problems your dosage levels might need to be considered in identifing the cause.
Thanks. You've pretty much confirmed my assumptions, and corrected some of my mistakes. To start I am going to consider this as a high light tank, and I need it to be a high light tank because of what I have growing in it. If need be I can hang a 70 watt MH over the bugger and run open top, and look into a chiller. I just really needed a baseline to get started with that is easy enough to adjust later.
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Old 06-06-2006, 07:32 PM
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Join Date: Jun 2005
Location: NC
Posts: 840
Yeah, it's so easy to overlook something when doing all these calculations that are based on calculations that are based on calculations, especially with such small numbers (but so many digits and decimals).

Quote:
I'm using AH reflectors, and the enclosure is completely lined with mylar. Lights sit about 2.5 inches above surface.
Using a hagen ladder with champange yeast for 3 bubbles/2 seconds ATM. Have an aluminum manifold with clippard valves being built and neoprene tubing on order. 87 pound tank in the garage already running one high light EI tank. (converted argon tank from a welding cart) Hopefully the industrial neoprene tubing will work for this 28' run.

Oh, so you *did* get the deluxe kit and you're running DIY Co2 with pressurized on the way? That's a horse of a different color!

You might want to consider upgrading your Co2 tank to something a little bigger.

Everything sounds great. Have fun pruning...more!

"Insanity: doing [or asking] the same thing over and over again and expecting different results."
random_alias is offline
Old 06-06-2006, 07:43 PM
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Join Date: Jun 2005
Location: NC
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Quote:
I was under the impression (likely the wrong one) that the K in KH2PO4 was chemically bound in a way inaccessable to plants.
I've always heard it being considered a K provider but I'll look for more info just to sure.

*UPDATE*

Just did some searching and everything I found talked about getting K from KNO3 and KH2PO4. To add some credibility, this included posts from Greg Watson. Never heard of it being bound but I have stuff stuck in my head, too. There was a time when I was mixing 1 tBsp of CSM+B in 500ml of water and calling it a standard solution! Luckily, I was dosing it in soft water and never noticed any deficiency.

"Insanity: doing [or asking] the same thing over and over again and expecting different results."
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Old 06-06-2006, 07:57 PM Thread Starter
Planted Tank Obsessed

Join Date: Oct 2005
Location: Bunker Hill, WV
Posts: 344
Quote:
Originally Posted by random_alias
I've always heard it being considered a K provider but I'll look for more info just to sure.

*UPDATE*

Just did some searching and found Greg Watson talking about getting K from KNO3 and KH2PO4. Also, everything else I found suggests that the K in KH2PO4 is available to plants. Never heard of it being bound but I have stuff stuck in my head as well. There was a time I was mixing 1 tBsp of CSM+B in 500ml of water and calling it a standard solution! Luckily, I was dosing it in soft water and never noticed any deficiency.
Danke schoen

As I said, I'll just write it off as mis-information. I'm far from a chemist, so I rely on those that are, or those that know those that are

Quote:
Originally Posted by random_alias
You might want to consider upgrading your Co2 tank to something a little bigger.
Heh...I got it from a paintball shop who was using it for a refill tank. Cost me all of \$150 bucks, over half filled . You should see the beast they replaced it with......
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