Backyard Aquaponics
A place to discuss aquaponics

Will try and work it out. do you have or will you have plants growing in or from the pond water? or is it just ornamental?

You may already know this AA but i'll post it for the benifit of others

GH is generally the concentration of magnesium and calcium ions in the water, doesn't really have much of buffering effect as it can come in many forms ie, magnesium nitrate, magnesium sulphate, calcium chloride etc. GH does not count towards KH unlessthe magnesium or calcium is tied to a carbonate cation

KH is generally the concentration of carbonate and/or bicarbonate cations could be calcium carbonate (not very soluble) or something like sodium bi carbonate (bicarb). With calcium carbonate it will also add to the GH as it contains calcium. In the bicarb example it will only raise KH.

AA your nitrate may also be contributing to the GH if they are tied to calcium or magnesium (very probable). The lime may be adding to the GH but not the KH and hence not having any buffering effect (also probable as the term "lime" is applied to at least three compounds! I think agricultural lime is calcium hydroxide, hence the high GH but not necessarily KH. AA just looked it up 200 to 400 PPM GH is only recommended for african cichlids, goldies and brackish water fish! I thought it sounded HIGH!

That's why I want to hook it to an 'Aquaponic Bank'. A rockery if you will of lava rocks and plants.

You still need to get the GH down though AA, even if all the nitrate is calcium and/or magnesium, its only going to lower the GH by 160PPM at max, and i'm tipping you don't want to run your nitrates at 0 ppm

I'll post a method for you by "close of aqua biz" tonight

AA,

I'm going to have to assume that the KH is quite low as your ph is quite low, but we have no way of knowing for sure.

What you need to do first, is reduce your GH considerably. You will need to do THREE 50% water changes to get your GH down to 118PPM. This will be important, because as we add KH the GH will go back UP point for point.

What you can then do is add calcium carbonate (in whatever form you like) best putting it into a few stockings and suspending it in the water, preferably in the water flow. this will slowly increase the KH over a week or two. You should be able to get a quicker response by adding powdered calcium carbonate to plain soda water and then tipping it into the pond. If sodium is not an issue then you can dissolve bi-carb into the pond water and you will have instant results. Get the first part done and then i'll talk more about raising the KH. Bicarb would probably still be fine to use, as long as its a once off.

Calcim carbonate has intricate relationship with dissolved CO2, can you give me more info on the pond? Waterfall? airaetion? number of fish? plant quatity?

If you're up for it you can read about it here, about half the articles are useful, some deal with marine aquariums and calcium dosing, so disregard those. http://www.thekrib.com/Plants/CO2/caco3.html

PS i would do the water changes over the space of about one and a half weeks.
Using the calcium carbonate in stockings method is nice as it takes a week or two the fish are not stressed

Steve

Makes perfect sense. I had asimilar plan but being a fish noob I needed you to hold me hand. Thank You.

The pond is a typical set and forget and decades later nephews and nieces still add goldfish randomly and wonder why things die in there.

No circulation nothing, a traditional western pond...

Needs to pimp it up!

actually the no ciculation will make it easier to get the KH up with calcium carbonate! It means that there wil be more dissolved CO2!

Personally i like crushed sea shells as calcium carbonate. Sometime dolomite is called garden lime. you can use this too, its a combination of magnesium and calcium carbonate.

No worries, just do your water changes and then the ultra high tech sock method just check PH every second day and maybe GH also.

Steve