Water Parameter questions

[Signus]

After reading up on how to dose CO2 according to pH and kH, I e-mailed the local water company asking for KH, GH, SO4, NO3, and PO4 in ppm. The director sent an email strait away as follows:

"The following data are composite values taken from recent finished water samples. They are good representations of the water delivered to our customers.

Sulfate: 75

Nitrate: 0.04

Calcium hardness, as Calcium Carbonate: 63.6

Total hardness, as Calcium Carbonate: 106

All units are mg/ L."

Forgive my ignorance here, but I assume "total hardness" is GH and "Calcium hardness, as calcium carbonate" is KH, correct?

Do we use -log(base 10) [x mg/L] formula to get GH and KH?

Was there a previous thread showing the ranges of "high", "medium", and "low" amounts of GH and KH?

 

[Tom Barr]

Sounds like good tap.
Ca hardness is alkalinity or KH, so 63 ppm of KGH, to get degrees, divide by 17.86.

63/17.86= KH
106/17.86 = GH also for GH.

Use only the the KH for pH/CO2 etc.
Also, see the drop checker method for CO2 measure.


Regards,
Tom Barr

 

[Signus]

KH = 3.5
Optimum pH = 6.6

According to Chuck's Planted Aquarium Calculater.

People mention using the glass checkers, but what's so wrong with using another means like this? No instant approximations of your CO2 levels?

Going to AHsupply 110w pc over the 29 gallon tank will be interesting. The first light should arrive within the week. -Or should I just stick with 55w since that gives ~2.2 wpg (The actual volume is more like 25 gallons. I measured during setup of the tank.)

 

[VaughnH]

There is nothing wrong with using Chuck's calculator unless you want to know how much CO2 is in the water. The calculator just doesn't work for the typical aquarium water we have. It will almost always give a much too high value for the ppm of CO2.

 

[Tom Barr]

Chuck's target CO2's are a bit low, bump everything up one section to the higher side.

That assumes that the KH is 100% bicarbonate, alkalinity can be influenced by a number of things, careful with that assumption

I've never seen a assumption that under estimates CO2 yet, there might be one, but I've never ran across it yet after decades.

So most assumptions tend to suggest that you have more CO2 than you really do...........so folks end up with algae due to low CO2.......thinking that are certain they have enough.

But it's still based on that original assumption.

KH ref solution gets around that, but the drop checker introduces others, slow response time, issues for some with using a precise pH color or measured value for pH, I use a pH probe and encase it in special membrane and KH ref solution to get around that.

Regards,
Tom Barr

 

[Signus]

KH ref solution gets around that, but the drop checker introduces others, slow response time, issues for some with using a precise pH color or measured value for pH, I use a pH probe and encase it in special membrane and KH ref solution to get around that.

-I don't think the professor I work for would appreciate borrowing the lab grade ph probe from our HPLC machine room. Even more so when he finds out it was used on a fish tank.

It sounds like a really good way to get the results you want, though. I guess it's time to make a drop checker out of some broken glassware and the bunsen burner. Thanks!

 

[BHornsey]

KH ref solution gets around that, but the drop checker introduces others, slow response time, issues for some with using a precise pH color or measured value for pH, I use a pH probe and encase it in special membrane and KH ref solution to get around that.

I agree, the colour change is a little slow on the drop checker.

I've never come across a probe membrane before. Is this a commercial offering and would you have a link to it?
I have an American Marine Pinpoint pH monitor in the tank. Not sure how accurate these are but it would be more useful to monitor this way.