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The Importance of GH Booster.

Dave Spencer

3 Jul 2007
N. Wales
Six months ago I moved house, a distance of approximately 10 minutes by car. The water in my previous house was very soft, and I didn`t expect the new house to be much different. Due to the softness of the water in the previous house I would add a little GH booster to my tanks at water change, just in case.

Over time, I reduced what I added to see if it was necessary. Lo and behold, I found that I didn`t need to add any, so I stopped adding it to all my tanks. Thinking my new water source was very similar, I refrained from adding GH booster to a new 120l I set up in the new house, plus the 60l which I had set up and matured in the old house, ready for moving my fish.

The 60l continued to flourish in the new house, whilst the 120l turned in to a bit of a disaster, with a type of brown fuzzy algae clogging up my Eleocharis parvula. It is a type I have never seen before in my tanks. My initial thoughts were to blame it on the very low plant mass I was starting out with. The 60l continued to thrive, being topped up daily with 1 litre of water to make up for evaporation, so I never suspected the change in tap water. There were signs, though. My two girls blonde, curly hair was behaving differently after being washed, but I didn`t give this much thought.

My 120l had CO2 levels way beyond yellow, yet nothing pearled, and the algae was taking over the tank. Flow was good, ferts were good, light was controlled for an immature tank, it was seeded with mulm, the filter had Purigen and Zeolite. The plants were out of my propagator, and none of the Crypts had melted. All I was achieving was a huge algal bloom, and a mysteriously dormant plant mass, yet still the 60l thrived.

Thinking of what the cause of the algae could be, I started to think about how Alison was adamant our water was softer, due to a change in the curls in the girls` hair. Going back to adding GH booster was the conclusion I came to. The 60l was doing fine without GH booster, but that had probably been able to build up Ca and Mg reserves from the previous house.

So, I added a pinch of GH booster to the 120l. That evening, when I came home from work the whole tank was fizzing like a lemonade bottle. I would never have believed that adding GH booster would have had this effect on my tank. I have also been able to pull the CO2 right back, too.

I took me two months of algified frustration to work out this simple solution. :rolleyes:

Hi Dave

Glad you stuck with it and got it sorted, and thanks for sharing your findings.

Dave Spencer said:
I took me two months of algified frustration to work out this simple solution.
As they say, it's only simple if you know the answer :thumbup:
But that is sometimes both the beauty and frustration about this hobby :D
George Farmer said:
Who would have thought the solution lay in observing female hair!? :lol:

Who needs test kits. :lol:
Great you got it sorted. Remember though that GH Booster contains quite a lot of potassium sulphate as well and it may be this that is causing your plants to suddenly pearl. From my own experience I've noticed that adding potassium has a greater immediate effect on plants than adding calcium or magnesium. It's just a thought and if you are already dosing plenty of KNO3 and KH2PO4 then you will already have plenty of K. If not then you could always add some potassium sulphate instead of the GH Booster and see what that does.

Interesting reading Dave, what's the science behind the GH booster and the algae going?
JamesC said:
.....Remember though that GH Booster contains quite a lot of potassium sulphate as well and it may be this that is causing your plants to suddenly pearl.

I never realised that there was potassium sulphate in GH booster.

The tank is EI dosed, so a K deficiency wasn`t something that I considered. It was a surprise how differently the plants are behaving now, and the only thing I have done differently is add GH booster. They have gone from being virtually dormant, to fizzing like mad. All I have to do now is get rid of the algae that got its feet under the table. :(
Jase said:
Interesting reading Dave, what's the science behind the GH booster and the algae going?

Plant health/growth.

The algae is still there, and will need manual removal, but I am now fighting a winnable battle. This is the tank that I had three filters leak on the floor when I was setting it up, along with a pressure gauge going on my CO2 regulator. If I get a nice scape out of this one, then I know I am in the hobby for the long haul. Setting this tank has been very trying.

Cool, probably wasn't potassium then. But yes GH Booster contains loads of potassium sulphate and depending what one you use it often has more potassium sulphate than the calcium and magnesium sulphate. Bit of a con really, at least Seachem call their one Equilibrium which is much more appropriate. They work well if used as you do with just a small amount but to add them to reconstitute RO water they send the TDS sky high which is why I don't use them but make my own.

Dave it's mostly likely due to low Mg, not the Ca++.

You can try dosing MgSO4 alone and see, might take a couple or 3 weeks before the tank gets limited again.
Mg is the central atom in Chl a etc.......it's got a lot of roles.
Ca.........I think plants are very good at getting this............Mg limitation is much more common and your description sounds more like Mg.

Tom Barr
Hi all,
Magnesium deficiency is a distinct possibility, I'm not sure about in aquatics but you see it a lot on garden/green-house plants. It has a distinctive look, with "interveinal chlorosis", tomatoes nearly always develop it unless you add extra mg (usually as "Epsom salts" in a foliar spray)



cheers Darrel
dw1305 said:
I'm not sure about in aquatics but you see it a lot on garden/green-house plants. It has a distinctive look, with "interveinal chlorosis",

It is the same in aquatics.

IME, starts off as yellowing round the edges of the leaves, that creep in, eventually leaving just the veining green and the rest of the leaf yellow.

After my first year stumbling into planted tanks I learned a bit more about the chemistry of what I was doing and put some requests into my water board for the exact make up of my tap water. Low and behold the low KH GH i knew about was actually compounded by a almost total lack of Mg.

I in turn learned that my trace mix didn't contain any extra so started adding Mg to my dosing schedule once a week to wondrous effects. Your doing EI, which trace mix are you using?

Interesting Dave, nice thread.

Ive never heard of this problem before. But then I guess I am only ust to either hardish water or remineralising RO. When doing that, I have to test the GH and KH so I know whats going on.

I know of another chap who doses extra GH booster ( Sera stuff ) to his tap water in Mold ( Which aint to far from you Dave ), but im not sure he does it for the same reasons. He keeps Rainbows.....

Does this not back up the thought that plants generally do better in harder water areas..... This wouldnt be a problem for those people.

Its interesting to know the science behind it, but for others is good to know its simply worth a try even if your not interested in the mumbo jumbo stuff behind it - which im not the biggest fan of.

Upping KH often gets plants moving in my experience, but im doing this with the Co2,KH,PH relationship in mind. Though it could also be having the same affect for the plants as yours are Dave.

The situation with your drop checker is interesting too. Was the drop checking going back to blue when the Co2 was off? If the water was very soft, then I would imagine it was yellow all the time? Yes?
This could also mean that if your water was naturally soft and acidic, then even just adding KH+ would have had the same effect....

All of the above is speculative, but I would be interested to see what the natural GH,KH and PH of your water was Dave.


In my mind all Dave's problems could have been avoided if he had used a test kit in the first place. Its therefore a prime example that test kits do still have a place in this hobby albeit with the understanding that they are only indicators as opposed to accurate results, with the notable exception of the nitrate home test kit which is completely useless.

They can certainly be useful to point the way forward.

Regards, Chris.
Hi all,
I'd certainly agree that nitrate test kits aren't very useful, but you can't really test for magnesium at home, the usual methods are by either "Flame Photometry" http://en.wikipedia.org/wiki/Photoelectric_flame_photometer (not particularly accurate) or by "Atomic Absorption Spectrophotometry" http://en.wikipedia.org/wiki/Atomic_Absorption_Spectrophotometry.

The GH value would help, but it would only tell you the amount of divalent ions (Ca2+ & Mg2+), and often the problem with magnesium deficiency is the Ca/Mg or K/Mg ratio (high levels of Ca and/or potassium (K) interfere with the uptake of Mg2+ ions), rather than the total amount of magnesium present.

Because magnesium sulphate is easily available (as the hepta-hydrate form "Epsom Salts" http://en.wikipedia.org/wiki/Epsom_salts) and not associated with toxicity to plants or animals, it's probably worth adding a 5 - 10ppm and seeing if your plants green up and/or improve in growth. If you have interveinal chlorosis (in the picture above) it is usually either Iron (Fe) or Magnesium (Mg) deficiency http://en.wikipedia.org/wiki/Magnesium_deficiency, and in many cases a problem with calcium interfering with uptake of Mg and/or Fe rather than a total lack of these elements.

cheers Darrel