# Barrs GH booster dosage?



## dukydaf (Dec 27, 2004)

Bert2oo1 said:


> 1 tsp is very different to 77g so my question is.. What dosage should I dose? This whole thing has got me very confused.


The correct answer is both  First you set your target parameters and then you dose for maintenance. 

Rotalabutterfly calculates the GH booster as a remineralization solution.... that is you add one time at *water change for the changed volume* and you get the desired parameters, say 5-6Gh. Unlike other nutrients Mg and Ca are not consumed in high amounts by the plants, but fish and invertebrates (and some plants) do better when the water conc. is high enough. This is the reason why we add some minerals to the soft water from the start. 

The GH Booster as described on barrreport.com is supposed to be added in *small quantities to the whole aquarium volume* to replace/add the small amounts of GH used by plants. It is mainly recommended for water that starts with low GH, like 4 or so. In a healthy planted tank this smaller dosage will not increase the GH so much (~0.3°dGH) but provides more than enough to cover plant consumption.



Bert2oo1 said:


> The mix I have made is
> 100g of Epsom salts
> 300g calcium sulphate
> 300g potassium sulphate.
> ...


Ahh... not so fast. One thing the originators of this formula do not detail about the 3:3:1 ratio(parts) is what is it a ratio of ? moles ? volume(tsp) ? mass ? I have searched far and wide and have not seen any pixels from either Colin or Barr clearly stating the answer. ( If somebody has the page please be so kind to link to it.) Making an educated guess, we would assume they are talking about mass.
The second thing is now your mass ratio is CaSO4(*2H2O):K2SO4:MgSO4(*7H2O) 3:3:1 and you want Ca:K:Mg 3:3:1 . Use the rotalabutterfly calculator with your ingredients to figure out what provides this ratio of Ca:K:Mg and then adjust the mix.

K2SO4 and CaSO4 are really not that soluble in water and you will have a hard time to make a worthy solution. If you can, consider replacing them with KCl and CaCl2 which are much more soluble.
I would advise against mixing up the salts together next time as they usually have grains with different densities which results in a heterogeneous mix, meaning you will not know if you have enough, half or no MgSO4 in that teaspoon. 

If you have any more questions, feel free to ask.


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## Bert2oo1 (Feb 16, 2017)

dukydaf said:


> The correct answer is both  First you set your target parameters and then you dose for maintenance.
> 
> 
> 
> ...




That's for the reply! Very helpful!

So I should ditch the mix I made and get some more chemicals? 

I put coral sand in my canister filter a few weeks back to buff my calcium and I dose 11g of Epsom salts at water change. My tank GH is 8 and KH 4. Do you think it's even worth dosing a booster with the coral and mg I already add? 

I've noticed my growth is abit stunted (mostly on rotala stems) but only on the new growth. 
I dose full EI kno3 and kh2po4. 
5ml seachem iron every 2 days and no micro's as I have a soil substrate. 

Is my problem most likely calcium and mg? 


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## nilocg (Jul 12, 2010)

I make the gh booster using 3:3:1 by weight, I started making it a long time ago and I was told this is what the original mix was so that is what I went with. I will look to find the reference but that was a long time ago so I dont remember where it was. Other than the fact that the dosing amount would change, I really dont think it matter if you mixed it by weight or volume to be honest.


You will not be able to make a liquid solution of this gh booster which will be concentrated enough to make it worth the effort.


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## Mango (Dec 12, 2015)

The Barr GH Booster calculator on rotalabutterfly is wrong.

To reach your target of 5 dGH you will need to add 80.01 grams (equivalent to 6 tbsp + 0 tsp + 1/2 tsp + 1/16 tsp + 1/32 tsp + 1/64 tsp ) Barr’s GH Booster to your 60gal aquarium to yield:
Element	ppm/degree
K	158.08
S	145.71
Ca	82
Mg	11.58
dGH	5

I would just use GLA GH Booster calculator since it's 3:3:3 and just do some changes to fit your requirement.


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## Zorfox (Jun 24, 2012)

Bert2oo1 said:


> My tank is a 60g.
> 
> The EI dosage guide says dose 1tsp of the Barr booster to a 60-80g aquarium.
> 
> ...


Nice catch Bert! You're correct to question those discrepancies. 

First off, your mixture is perfectly fine. That's Barr's GH booster.

I hate to say it but the sticky is wrong. As far as Rotala, remember, they are still testing. However, they are targeting an increase in GH of 5 degrees. In fact, it should be 2 degrees. If you change that it will report to dose 32 grams and a long list of volume measures which basically equal about 5 1/2 teaspoons. I have written my own *free Windows based calculator*. My calculator reports 26 grams or approximately 6 1/4 teaspoons.

I'd be happy to bore you with the reason for the small discrepancies but why? The calculators are both more than close enough albeit mine is more accurate lol. 

To be honest, just add enough to raise the GH 2 degrees. There are plenty of cheap GH test kits that work well. That way you know it's accurate. :wink2:



dukydaf said:


> Ahh... not so fast. One thing the originators of this formula do not detail about the 3:3:1 ratio(parts) is what is it a ratio of ? moles ? volume(tsp) ? mass ?


Mass. All the calculations are done based on mass. The teaspoon measures are near approximations. 



dukydaf said:


> The second thing is now your mass ratio is CaSO4(*2H2O):K2SO4:MgSO4(*7H2O) 3:3:1 and you want Ca:K:Mg 3:3:1 . Use the rotalabutterfly calculator with your ingredients to figure out what provides this ratio of Ca:K:Mg and then adjust the mix.


Actually, Tom Barr suggested mixing CaSO4.2H2O (3 parts) , K2SO4 (3 parts) , and MgSO4.7H2O (1 part). Then use to maintain a GH of 3-5. 

However, I agree with you. I think that is pretty high in Ca and low in Mg. 

If we do the molar calculations on a mixture that Tom Barr suggests we get a substance containing the following. 

1.890 % Mg
9.351 % Ca
18.2451 % K

That's a 9:2 ratio of Ca:Mg. 

Hoagland solution is 4:1 (Ca:200 ppm , Mg:48 ppm) of elemental Ca and Mg. :icon_idea



nilocg said:


> I make the gh booster using 3:3:1 by weight, I started making it a long time ago and I was told this is what the original mix was so that is what I went with. I will look to find the reference but that was a long time ago so I dont remember where it was. Other than the fact that the dosing amount would change, I really dont think it matter if you mixed it by weight or volume to be honest.
> 
> 
> You will not be able to make a liquid solution of this gh booster which will be concentrated enough to make it worth the effort.


This has always been my understanding. Most calculations and/or discussions use mass for these references.


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## Bert2oo1 (Feb 16, 2017)

Zorfox said:


> Nice catch Bert! You're correct to question those discrepancies.
> 
> 
> 
> ...




Thanks for the info! So if I add 26g after every 50% water change then I should be good? Should I remove the crushed coral from my filter if I'm adding this much? 

I'm glad I'm not going crazy haha 


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## Zorfox (Jun 24, 2012)

Bert2oo1 said:


> So if I add 26g after every 50% water change then I should be good? Should I remove the crushed coral from my filter if I'm adding this much?


Yes, 26g (about 6 1/4 teaspoons). I would remove the coral if you're adding GH booster.


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## Bert2oo1 (Feb 16, 2017)

Zorfox said:


> Yes, 26g (about 6 1/4 teaspoons). I would remove the coral if you're adding GH booster.




Awesome! Thanks  

One concern I have tho is the amount of K I'll be dosing. I dose kno3 and kh2po4 so my K will be up around 58.83ppm of K including the GH booster. Seems abit high? 


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## Zorfox (Jun 24, 2012)

Bert2oo1 said:


> Awesome! Thanks
> One concern I have tho is the amount of K I'll be dosing. I dose kno3 and kh2po4 so my K will be up around 58.83ppm of K including the GH booster. Seems abit high?


Your numbers are wrong. If you dose full EI, in one week you will have added the following macro nutrients, including GH booster. 


```
NO3	22.5
N	5.083
PO4	3.9
P	1.273
K	32.53
Ca	8.58
Mg	3.47
dGH	2
S	18.3
```
That said lets be clear. GH booster IS part of the EI method. Far too many forget this. The extra nutrients from GH booster will have little impact on most tank inhabitants and all the plants. 

It's funny you should mention the extra potassium (K). Of all the nutrients, potassium is probably the safest to overdose. You would have no issues even at 100ppm of potassium.


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## dukydaf (Dec 27, 2004)

@nilocg and @Zorfox thank you very much for your responses and corrections. It seems my logic replaced my memory …more on this later but first I was able to find some statement Barr made on this topic:



> GH range 3 degrees ~ 50ppm or higher
> …
> You can use SeaChem Equilibrium for this or a mix of CaCl2 (or CaSO4 although it is not as easy to dissolve into water) and MgSO4 at a 4:1 ratio to increase GH. You can add this without knowing what your GH is by adding 1 degree's worth after a weekly water change (or slightly less with less frequent water changes)
> …
> If you also add the GH booster suggestions in this, then you will have a higher range of K+, about another 10-20ppm.


Source: Tom Barr on The Estimative Index of Dosing, or No Need for Test Kits - Aquarium Plants - Barr Report
From this I understand the following:
When re-mineralizing you should target a level of at least 3 degrees (assuming °dGH)
As a fertilizer, it should add about 1 °dGH. The mix is also meant to increase the K+ by 10-20ppm in addition to the 20-30ppm coming from other fertilizers used.



> You might consider making your own from the base chemicals.
> 2 parts: K2SO4: potash of sulfur
> 1 part: CaSO4: Gypsum
> 1 part: MgSO4 Epsom salt
> ...


Source: Tom Barr comments on GH booster Europe - Aquarium Plants - Barr Report

Here Barr states that the GH Booster is based and meant to be similar to Seachem Equilibrium. Additionally that the K+ ppm are targeted to be similar to NO3- or “a little higher” and that the GH booster is added more for Mg++ and K+

A ratio without a type/unit tells you nothing 
1 : 3 : 1 : 2 rice : water : flour : potato –>meaningless
Presuming a unit/type of measurement can lead to severe problems and given the weird preference of measuring the weight of salts with teaspoons present on that and this site… who can tell. But thanks to nilocG we know this is actually a mass ratio.


nilocg said:


> I make the gh booster using 3:3:1 by weight


But wait, it seems like somebody did something to the pooch and missed the targeted ratios…
Barrand aquariumfertilizers.com suggest a mass ratio of 
3:3:1 CaSO4: K2SO4:MgSO4
Whereas most of us (even the producers?) will use the chemicals described by Zorfox


Zorfox said:


> First off, your mixture is perfectly fine. That's Barr's GH booster.
> Actually, Tom Barr suggested mixing CaSO4.2H2O (3 parts) , K2SO4 (3 parts) , and MgSO4.7H2O (1 part). Then use to maintain a GH of 3-5.


I have to disagree, that is not the GH booster as suggested by Barr. Barr actually suggested
3:3:1 CaSO4 : K2SO4 : MgSO4 – meaning a mass ratio of  4.4 : 6.7 : 1 Ca : K : Mg
But what we get is 
3:3:1 CaSO4.2H2O : K2SO4 : MgSO4.7H2O – meaning a mass ratio of  7 : 13.7 : 1 Ca : K : Mg
For reference the Seachem Equilibrium has a mass ratio of 
3.33 : 8.1 : 1 Ca : K : Mg


Zorfox said:


> Hoagland solution is 4:1 (Ca:200 ppm , Mg:48 ppm) of elemental Ca and Mg. :icon_idea


Now how is that for a change in ratios due to simply ignoring the hydration level. Are the manufacturers using anhydrous salts ? Unlikely. 
So it seems pretty clear to me that the plan was to get close to 4:1 or 3:1 Ca:Mg ratio but at one point the hydration levels were ignored. The ratio itself does not need to be spot on for aquatic plants but 7:1 Ca:Mg is too much Ca. This becomes a problem when you target a low GH environment , such as for fancier shrimps as you are either under-dosing Mg or increasing the TDS without reason. 



Bert2oo1 said:


> One concern I have tho is the amount of K I'll be dosing. I dose kno3 and kh2po4 so my K will be up around 58.83ppm of K including the GH booster. Seems abit high?





Zorfox said:


> It's funny you should mention the extra potassium (K). Of all the nutrients, potassium is probably the safest to overdose. You would have no issues even at 100ppm of potassium.


And by re-mineralizing with this GH Booster (hydrated edition) you can easily go over 100ppm K+. Given 50% weekly water change and extra K from KNO3 you will be above 300ppm K+.
Let us also look at what happens when you try to use GH Booster (hydrated edition) as a remineralizer to get to a decent 5 °dGH . 
82ppm Ca 
158ppm K
12ppm Mg

How is the 158ppm K in line with Barr’s recommended use of adding 10-20ppm K from the GH Booster. What about his idea of keeping the ppm of K about the same or “a little higher” as NO3- ? Something, somewhere went wrong.
It seems clear and rational that the main use of the GH Booster is mainly to make sure enough Mg is present and does not bottom out. Indeed, most Trace mixes provide some Mg and K but no Ca. The GH Booster mix with the hydrated salts focuses instead on adding a lot of Ca and way up there K. In my opinion this makes it unsuitable for remineralization and to be avoided for all applications where a low TDS is needed.



Bert2oo1 said:


> So I should ditch the mix I made and get some more chemicals?
> I put coral sand in my canister filter a few weeks back to buff my calcium and I dose 11g of Epsom salts at water change. My tank GH is 8 and KH 4. Do you think it's even worth dosing a booster with the coral and mg I already add?
> I've noticed my growth is abit stunted (mostly on rotala stems) but only on the new growth.
> Is my problem most likely calcium and mg?


I would keep the mix and dose to reach my target Ca level than add extra Mg source to reach the originally desired 4:1 ratio. Mix the bag well before dosing so that the salts are somewhat uniformly distributed. 
With the filter setup you describe I would not worry about Ca but actually dosing gives you more control. Unlikely the rotalas are stunted because of Ca or Mg.


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## Zorfox (Jun 24, 2012)

Here’s the thing. Tom Barr was never very specific in regards to the “manufacture” of GH booster. 



Tom Barr said:


> “You can use SeaChem Equilibrium for this or a mix of CaCl2 (or CaSO4 although it is not as easy to dissolve into water) and MgSO4 at a 4:1 ratio to increase GH.”


CaSO4 29.4387 % Calcium
CaCl2 36.1115 % Calcium

That’s a pretty big variance already. Also, is the MgSO4 exactly that? anhydrous? Or is it what 99% of us have, MgSO4.7H2O? Is it by fertilizer weight or molar mass calculations (meaning CaSO4 and CaCl2 would not be equal)?

I’m in no way speaking for Tom. However, if he were to weigh in I suspect he would say something like “what’s the difference? As long as we’re supplying adequate calcium and magnesium plants will flourish. You would be hard pressed to cause issues by adding too much”.

Basically, I think his point would that we don’t need to be as accurate as we think. Add enough nutrients and garden. Quit over thinking things.

Oddly enough, this works QUITE WELL lol. 

Let me first say that I agree with you dukydaf. These types of issues bother me. I like accuracy. I know it’s not that important but it is what it is. My beef is that we all basically buy the same chemicals. If we can’t use the hydrated forms, why is this news after how many years? Lets look at the GH booster you get from Planted Aquarium Fertilizer.



Planted Aquarium Fertilizer said:


> “Tom Barr's general water hardness booster contains: 3 parts Potassium Sulfate, 3 parts Calcium Sulfate, 1 part Magnesium Sulfate by weight. 1 lb:."


Now lookup what they sell as CaSO4.



Planted Aquarium Fertilizer said:


> Calcium Sulfate
> 1 lb CaSO4
> AKA Gypsum supplies calcium to plants without increasing alkalinity.


Gypsum? That’s not CaSO4 is it? 

Nope, but it’s close enough. We all use it. Gypsum is CaSO4.2H2O. 

Don’t get me started on the common errors that can be made. Example, look at the nutrient ratios for a 10% Hoagland solution. Odd how close those numbers are to what Tom Barr recommends. But wait, N and P are not the same as No3 and PO4, right…?


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## Bert2oo1 (Feb 16, 2017)

Zorfox said:


> Here’s the thing. Tom Barr was never very specific in regards to the “manufacture” of GH booster.
> 
> 
> 
> ...




Thanks Zor and duk! Great info. 

After reading your advice and doing abit of my own research ive decided to just dose mgso4 and caso4 seperate to mid range EI targets. 
I'll be dosing 16g calcium chloride and 16g of Epsom salts. Giving me 20ppm of C and 7ppm of MG. 

I'll also be removing the coral from my filter. 

My next question is. Once I do a large water change (90%) to bring my water back to resting level and dose my 16g of each to get my desired levels, do I then half the dose for every week after that (8g and 8g) to keep my levels stable after a 50% water change? Or do I just dose 16g of each after every water change? 


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## Zorfox (Jun 24, 2012)

*Here we go again lol.*



Bert2oo1 said:


> Thanks Zor and duk! Great info.
> After reading your advice and doing abit of my own research ive decided to just dose mgso4 and caso4 seperate to mid range EI targets.
> I'll be dosing 16g calcium chloride and 16g of Epsom salts. Giving me 20ppm of C and 7ppm of MG.


Here we go again lol. 

CaSO4, Calcium Chloride, MgSO4 and Epsom salts are all different chemicals. I know it sounds crazy but these basic chemistry errors can cause huge calculation errors. Here are the most common forms of Calcium and Magnesium.


```
CaCL2.2H2O	15ppm	12.5gm (approx. 3 1/2 teaspoons)
CaSO4.2H2O	15ppm	14.6gm (approx. 4 3/4 teaspoons)
MgSO4.7H2O	5ppm	11.52gm (approx. 2 1/4 teaspoons)
```
I know it's not 20ppm Ca and 7ppm Mg. Just use my numbers. 15 and 5 are easy to remember. Your plants will not use that amount in a week. Oh, did I mention it's 3 dGH which is within the EI dosing recommendations?

Verify which type of calcium you have first. As far as the magnesium if you bought epsom salt then it should say Magnesium Sulfate Heptahydrate on the back. That would be MgSO4.7H2O



Bert2oo1 said:


> I'll also be removing the coral from my filter.


 If you're dosing EI then you might as well. Your fish may thank you but your plants really wouldn't care.





Bert2oo1 said:


> My next question is. Once I do a large water change (90%) to bring my water back to resting level and dose my 16g of each to get my desired levels, do I then half the dose for every week after that (8g and 8g) to keep my levels stable after a 50% water change? Or do I just dose 16g of each after every water change?


No. Simply continue dosing the same amounts. With the weekly 50% water changes the levels eventually stabilize.


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## Bert2oo1 (Feb 16, 2017)

Zorfox said:


> Here we go again lol.
> 
> CaSO4, Calcium Chloride, MgSO4 and Epsom salts are all different chemicals. I know it sounds crazy but these basic chemistry errors can cause huge calculation errors. Here are the most common forms of Calcium and Magnesium.
> 
> ...




Awesome thanks for your help Zor! I think I've got a great place to start now! I'll be starting with the new doses on Sunday after my water change! 


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## dukydaf (Dec 27, 2004)

Bert2oo1 said:


> My next question is. Once I do a large water change (90%) to bring my water back to resting level and dose my 16g of each to get my desired levels, do I then half the dose for every week after that (8g and 8g) to keep my levels stable after a 50% water change? Or do I just dose 16g of each after every water change?
> 
> 
> Sent from my iPhone using Tapatalk


what Zorfox said plus 

If you dose 2X to remineralize the whole aquarium, when you do a 50% water change you only need X to get the same levels for GH. Basically you only remineralize for the volume of water replaced. If you have sensible fish you can do this outside the aquarium and also match the temperature.


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## Tom Barr (Nov 16, 2012)

Generally, I'll add about 1 table spoon of GH booster(Ca/Mg only, no K2SO4 like SeaChem) 1-2x a week per 60 gallons of tank. This is enough even if you have soft low GH tap water and you have the pickiest rare hard to grow plants. 

It is assumed we are talking about CaSO4 as the 2H2O form and the epsom salt you get most places is going to be MgSO4 7H2O.
Yea, there are other forms, but these are the most common and what are used by Sea Chem and most vendors selling GH booster. 

Gh is relatively easy. Some add the K2SO4 if they do not use much KNO3 or KH2PO4 for their tank(eg, high fish load, lower light, non CO2 etc)
That is typically 2:1:1 K2SO4:CaSO4:MgSO4
SeaChem adds a like Mn and Fe as sulfate salts, but unless it is chelated, the Fe will need reduced by the plant or the soil needs to be reductive enough to reduce the oxidized form of Fe. The same is less true for Mn. 
Never was clear on why Greg Morin decided to add those two. 

Keep the GH booster in an air tight container also, it'll turn into a brick otherwise. 
Ca, Mg, K+ are mostly taken up via the leaves for most aquatic weeds. But many of our plants are amphibious........so without any water, they obviously have little choice but the sediment. 

Note, you can modify EI to suit. Some do larger water changes, and/or 2x week to keep tighter control. Some stretch out the water changes to every other week. 
Some mix limited testing in and modify based on the results.
Others use a conductivity meter and change based on a range in uS.

Quite a few ways to fry this fish.


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## Bert2oo1 (Feb 16, 2017)

Tom Barr said:


> Generally, I'll add about 1 table spoon of GH booster(Ca/Mg only, no K2SO4 like SeaChem) 1-2x a week per 60 gallons of tank. This is enough even if you have soft low GH tap water and you have the pickiest rare hard to grow plants.
> 
> 
> 
> ...




Thanks Tom, I've ended up going 11.5g caso4 and 12.5g mgso4 dosing seperate. I decided to dose k2so4 to mid range EI aswell. 

The improvement has been amazing. Plant growth is really starting to take off. Another month or so and I'll be able to push the lights abit more 


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## Tom Barr (Nov 16, 2012)

EI was NEVER suppose to be technical, that's the point. 

But folks wanna over analyze and think some fine details on their dosing routine is the cat's meow.

It is not.

I'll give you two examples:

No ferts or water changes:










And this with plenty of ferts and water changes:










Key points: good T5 lighting, Rich stable CO2 and ADA AS

Plants grow in both cases. 

for all the hollering about ferts...........and there's plenty of hollering..........they are much less critical than many suggest.
If you are off by a few %, no big deal. 
Main thing is to not run out and have them available "somewhere". Sediment is a good place and pretty easy. So is the water column.
So are both. But either or works also.


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## cryptopi (Jan 5, 2018)

Great info. Tagging it for future reference


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