Backyard Aquaponics
A place to discuss aquaponics

Interesting how subtle vb was in getting me to help in straightening out his shed - moved a few empty fishtanks and grow beds around and it is now livable (well it was when I left).

Good to see your setup and loved to see how the compost worms were doing in the GB

Yeh thanks for being kind enough to take that beautiful 1000 litre purpose built aquaculture tank off my hands (albeit temporarilly) Les. Makes my shed so much neater

An update:

I have noticed that the KH of the system has been dropping from what I got it up to my putting the CaCO3 in a couple of weeks back. Ph is steady at 7.2 - but I want to be proactive not reactive, so want the system well buffered.

Today I put another 300grams of CaCO3 into the system - but first I took some readings:

Ammonia - 0
Nitrite - between 0 and .25
Nitrate - didn't test
dKH - 3
dGH - 21 ( )

Will test again in a couple of days to see what effect this addition has had on KH and GH.

Les you are lucky, you only had to help move the tanks in the shed I had to help move them from gympie. LOL

Ap

VB, will be definatly interested in the new KH level.

WOW, GH is getting well up there........ I've probably mentioned it before, but my theory on this is;

CaCO3 is quite insoluble, so the GH will only go up by the same amount as the KH initialy

As the CaCO3 is dissolved by the acidic nitrification process, the CO3 (KH) is "used up" (chemically changed) (so the KH may drop)

The Ca (GH) however will still be in solution (as part of another compound formed from the CO3.

So as the CaCO3 is contiunually dissolved, the GH will continue to rise, it will only be removed from the system by plants that are naturally high in calcium or by water changes.

Make sense to anyone?

Steve

Yep - I wonder what GH levels the perch handle as a maximum.

saw a table once..............................will have to try and find it on the net again.

You're not thinking about this are you Steve here

nope, i was a ridiculously complete table for tolerance levels...............no doubt i saved it in a safe place or book marked it into my un-navigatable fav. list.

Did some tests this morning. Reason for tests was:

1. wanted to find out what affect the addition of another 300gms of CaCO3 on 18 March has had.

2. Added some Min Plus rock dust to the system today (100 grams) and wanted to have a baseline test before adding to see what affect it has on GH & KH.

Results of tests:

Ammonia - 0
Nitrite - .25 (happy with these as I fed quite heavilly yesterday - because I was home)
Nitrate - bloody high, climbing towards 160
PH - stable at 7.2
KH - 3 dKH
GH - 25 dGH

The KH reading is interesting in that it has not gone up any from the 18th. Though it should be noted that a lot of the CaCO3 can still be seen if I dig into the gravel where I burried it. It should dissolve as it is required.

As I may want to get the GH down some - I tested my tap water to see what I would be replacing it with.

Tap water test:

dKH - 4
dGH - 5

I planted some cucumber seeds in my system a few weeks ago and they came up well. I have thinned them and the plants I left have been growing well. Today however I have noticed that the stems of the plants (all of them) have split from gravel level for a couple of inces up the plant. I expect this is due to the water that they are receivign and the fact that the stems have increased in size quicker than the skin of the plant can handle. Has anyone else experienced this issue? I am hoping the stems will heal (by forming a new layer of skin where exposed from splitting) and plants will continue to grow.

VB, I read an article on hydroponics that said just what you did. The ideal conditions make growth outstrip outer surface ability to cope. This can happen to fruit as well as stems. They suggested special varieties developed for greenhouse/hydroponic production. They have been bred for these conditions. Just for fun, I looked for these on the web. The ones I found, the seeds cost 4 times what I pay. They did say some normal varieties are resistant to splitting (no examples were given).

It would be a great use of this forum to share successful veg variety information. It would be nice to start such a topic unless a current topic fits. I am just starting now and have no proven winners yet. I would really value forum member advice. The oz advice might not work for me...or would it? Maybe the common factors prevail. But then, my seed suppliers may not have oz fruits.

I think the ones I planted were Lebanese cucumbers - so I guess I can strike those off as being unsuitable. A shame because lebanese ones are my favourites. I looked again and the splits are way longer than 2 inches - definitelly no good..

I know others here have grown cucumbers without trouble - so I guess I should try the other varieties.

Good idea about the new thread Doug - I will start it up.

I know dKH has been beaten to death already, but I have a very high end number. My tank water is 12 and the well water is 14. That is higher than I have heard here. Is that too high? The pH is about 7.9. I would like to see what the bacteria will do with that when they get going, but is that so high the vegies will curl up and die? The 500 fish arrive in a couple of weeks. What will they think of this? Nitrite is about 4.0 (I am cycling with ammonia. The ammonia dropped from 5 to 2ppm so far and made alll that nitrite. Nitrate is still 0.0. I do not have a dGH test kit yet.

Is this hijacking VB? My net etiquette is still forming. Your posted numbers made me worry about my numbers. I can move these questions to my system topic, if that is better.

No probs leaving it here Doug at this stage.

Plants traditionally grow best in PH between 6 & 7, though will handle PH up to the high sevens. I don't think 7.9 will be good for plants or fish. In the long run you should be okay because the nitrification process will push PH down and your water will buffer it at about 7.2 (which is what I and many others keep their systems at by adding CaCO3 in the form of shell or powder). THe challenge is what to do until nitrification pushes you down to where you want to be (it could take a while - I don't know). You may need to add an appropriate acid at the start. Is it possible for you to use some rainwater at first?

In relation to fish tolerances to PH and the ability for the bacteria to work at these high PH levels I would need to look around a bit more. Maybe do a google on the Tilapia tolerances DB.