Very low GH and KH

dantra

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I checked my water and found that I may need to independently dose calcium sulfate and magnesium sulfate. The reason I say that is because my GH and KH oddly both tested 2.24. My pH was 5.5 but I think is lower, read more like 5.0-4.5 according to the test.
I dose 1/4 teaspoon GH Booster with a 50% water change once a week.
A little under 1/4 KNO3 - 3x week
Just a little more than 1/16 tsp. of KH2PO4 - 3x week
I dose just a little more than 1/16 tsp. of CSM+B Plantex - 3x week alternating days from above.

So what more can I do to "normalized" or better put, raise my KH?
Is my concern for dosing Calcium and Magnesium warranted or do I just dose magnesium?

By the way the tank is fine.
 

Tom Barr

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Leave the KH alone, add more GH. A good general rule unless you want to reduce the KH.........

Regards,
Tom Barr
 

dantra

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Okay, raising GH which is basically general hardness (Mg & Ca) will do the trick?
 

Philosophos

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Mg, Ca and somewhat S. Look at the general ratios of what's required; you won't find anything strict, but you should find some general guidelines. Ca is hard to avoid, but if it's not in your tap you can add it without adding to anything besides GH through CaSO4 or CaCl2. MgSO4 shows up in a lot of tap, and it's dirt cheap to add as MgSO4.7H2O (epsom salts) from the grocery store. S should tag along just fine from the K2SO4 required to get K+ into most ideal ranges besides the use of KH2PO4 and KNO3.

-Philosophos
 

dantra

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I do have K2SO4 but only add that twice a week because at the beginning of the week its added (included) in the GH Booster. So I do add K2SO4 Tuesday and Thursday. Forgot to mention that.

CaSO4 is also included in the GH Booster. I'll I continue to add CaSO4 twice a week (Tuesday and Thursday) along with Mg and keep an eye on things.

Its like GH is bottoming out by mid week and at the end of the week its almost nonexistent.
 

Philosophos

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My first question would be how much are you adding to what volume of column? Also, what's in your filter? Either the plants are sucking it up or something else is. Perhaps the test kit is wrong as well; did you calibrate it and test just before and after adding the GH booster?

-Philosophos
 

Tom Barr

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I'd add maybe 2 GH extra, that should more than enough for the plants.

Regards,
Tom Barr
 

dantra

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Here's what's added to 18 gallons of water:

Sunday - water change - add 1/4 tsp. of GH Booster
A little under 1/4 tsp. of KNO3
A little more than a 1/16 tsp. of KH2PO4

Monday - A little more than 1/16 tsp. of CSM+B Plantex

Tuesday
A little under 1/4 tsp. of KNO3
A little more than a 1/16 tsp. of KH2PO4
1/32 tsp. of K2SO4

Wednesday - A little more than 1/16 tsp. of CSM+B Plantex

Thursday
A little under 1/4 tsp. of KNO3
A little more than a 1/16 tsp. of KH2PO4
1/32 tsp. of K2SO4

Friday - A little more than 1/16 tsp. of CSM+B Plantex

Saturday - rest day

I add a purigen bag at every filter cleaning which I've done from day one. I haven't experienced any ill affects from purigen at all. Like I mentioned above, by the end of the week GH and KH is almost non existent.
 

Philosophos

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Well here's what I got from my newly made calculator as your weekly dosing routine in ppm's, not accounting for your "slightly more/less":

N: 31.59241654
P: 9.678921939
K: 30.34101373
Ca: 1.29152035
Mg: 0.263196155
Fe: 0.695408162

With a little messing around for the more/less it looks like:

N: 37.91089985
P: 11.61470633
K: 36.40921647
Ca: 1.54982442
Mg: 0.315835386
Fe: 0.834489795

You could probably scale back everything a bit unless your tank is running high pace. You'll find nonlimiting levels in most tanks sit at 2/3 of your current N and K, easily 1/4 or so the PO4. I'm not suggesting that you're doing any harm by a long shot, but you can get more for your dollar on these ferts without much issue.

The GH is definitely being dosed low. As Tom says, a couple degrees more wouldn't hurt. Alternately you can use epsom salts and CaSO4 or CaCl2 to do the job; it's cheaper to buy the epsom salts at the store and calcium on its own rather than paying for it in GH booster premixed.

Careful if you go the CaCl2 route; premix the stuff ahead of time and wait for it to cool down. Use gloves and glasses or your cuticles and eyes may hate you for it. Alternatively, make a stock solution of pure CaCl2. Don't add the MgSO4 unless you know how... I've had tons of issues so far, and I still haven't gotten it to combine in a stock solution in a stable way.

-Philosophos

*edited for some minor corrections on the calculator; I just got it running today*