Backyard Aquaponics
http://www.backyardaquaponics.com/forum/

Sources of potassium
http://www.backyardaquaponics.com/forum/viewtopic.php?f=3&t=6117
Page 1 of 2

Author:  Jono [ Sep 8th, '09, 12:27 ]
Post subject:  Sources of potassium

Has anyone used muriate of potash (which is just potassium chloride) or sulphate of potash (which is just potassium sulphate) in there systems?
I have a potassium deficiency and can get as much as i want of both of these from work (the joys of workin at a fertiliser plant :D ).
I'm leaning towards the sulphate of ammonia tho, coz i don't really want to be adding anymore cholrides to the system and sulphate is useful as a source of sulfur.
Any opinions??
Cheers
Jono

Author:  Uncle Yarra [ Sep 8th, '09, 18:58 ]
Post subject:  Re: Sources of potassium

I'd probably lean towards the sulphate, but not without trying the concentration you want to use in a sample of the water just to make sure the pH doesn't go spacko.

Author:  TCLynx [ Sep 8th, '09, 21:40 ]
Post subject:  Re: Sources of potassium

I've used murate of potash early on when I couldn't find maxicrop.

I'd be interested in what your research finds out about the potassium sulfate and it's effects on pH and such. Might also want to make sure not to overdo the sulfer though but small amounts would probably be ok.

Can you get potassium bicarb?

Author:  Outbackozzie [ Sep 8th, '09, 21:42 ]
Post subject:  Re: Sources of potassium

I have recently added 2kg of P. Sulphate to my system in an attempt to get my pH back above 6, and it did not move. 12,000 litres of water.

Author:  TCLynx [ Sep 8th, '09, 21:52 ]
Post subject:  Re: Sources of potassium

I wouldn't expect potassium sulfate to raise system pH. As it breaks down though, I might expect to see the sulfur to lower the pH.

Author:  Outbackozzie [ Sep 8th, '09, 21:53 ]
Post subject:  Re: Sources of potassium

hey?? oh noes lol

Author:  TCLynx [ Sep 8th, '09, 22:02 ]
Post subject:  Re: Sources of potassium

I think potassium chloride is more likely to raise pH but at the amounts we normally use in AP, I don't think it would be all that effective and I doubt you would really want to use too much as you only really want chloride when dealing with nitrite spikes.

Author:  Outbackozzie [ Sep 8th, '09, 22:03 ]
Post subject:  Re: Sources of potassium

I best be going to bunnings tomorrow and getting some EcoRose and adding a small amount....low pH = high ammonia.

Author:  TCLynx [ Sep 8th, '09, 22:06 ]
Post subject:  Re: Sources of potassium

Again OBO? What happened to your rock solid 7.6 pH anyway?
Well, don't overdoo the potassium since you already added potassium sulfate.

Perhaps you need to get a little bag of lime too since calcium is also needed by plants.

Author:  Outbackozzie [ Sep 8th, '09, 22:14 ]
Post subject:  Re: Sources of potassium

Still got quite a bit of shellgrit slowly dissolving....

So lime hey? Any thing in particular to look out for?

The pH rapidly dropped about 2 months ago from 7.6 to the low 6's, and has been steadily dropping since. All my buffering obviously got used up. Still went for a year without any problems :)

I must admit that the low pH does not seem to have affected the fish or plants badly at all. I have had no fish mortalities all winter, except for the black bream, which do not like the cold.

I would just like to be able to get the pH back to a readable point on the chart :)

Author:  TCLynx [ Sep 8th, '09, 22:25 ]
Post subject:  Re: Sources of potassium

Well I don't know what exactly eco-rose is since we don't have it around here but for some reason I'm thinking it is potassium bicarbonate.

calcite limestone or Calcium carbonate will raise pH and provide calcium. Go slowly when adding it as you don't want to overdoo.

dolomitic limestone is calcium magnesium carbonate. Will also raise pH while providing calcium and magnesium.

Many garden limes in the garden centers are actually a mixture of both limestones. With lime, you want to be careful adding it to the system since overdoing it could leave you with a pH way too high too fast and it will take a long time to come back down.

Author:  RupertofOZ [ Sep 8th, '09, 23:18 ]
Post subject:  Re: Sources of potassium

Or "hydrated" or "slake" lime OBO... Calcium Hydroxide... commonly used by brickies...

A very strong base... use cautiously.... I use a heaped handful in 6000L to bring pH back about 0.4.... and that was within an hour... :shock:

BiCarb of Soda... Sodium BiCarbonate.. is another alternative....

And yes TCL... EcoRose is Potassium BiCarbonate.... and a very good, quick buffer...

Author:  Food&Fish [ Sep 9th, '09, 06:01 ]
Post subject:  Re: Sources of potassium

Outbackozzie wrote:
I have recently added 2kg of P. Sulphate to my system in an attempt to get my pH back above 6, and it did not move. 12,000 litres of water.

Hi OBO i see your system has drifted to what did it get down too
What are you doing about raising it Rupt has mentioned slacked lime where would you find that
I wonder what joles older system is running atm that would have to be 4 years old now !

Author:  Snakes [ Sep 9th, '09, 06:14 ]
Post subject:  Re: Sources of potassium

I remember someone talking about the plant Comfrey being high in potassium, and to put it in a container and in a dark place to go to mush, then applying as a spray? I may be wrong??? :D

Author:  Outbackozzie [ Sep 9th, '09, 06:35 ]
Post subject:  Re: Sources of potassium

Hi FF, it is currently off the bottom of the pH chart, so I dont know how low it is, this is causing ammonia and nitrite to be pretty high, not toxic levels, but I dont want any of it.

I'll go to bunnings today and see if I can find some lime, and I'll add a little bit at a time during the day and test the pH after each dose.

Rupe you said 'bring pH back' did you mean back up?

Page 1 of 2 All times are UTC + 8 hours
Powered by phpBB® Forum Software © phpBB Group
https://www.phpbb.com/