Backyard Aquaponics
A place to discuss aquaponics

Yep - I've since got a calcium test kit and there is no way that in summer I have low calcium levels, if anything the opposite is true my source water is quite high in calcium and with excessive evapotranspiration it tends to accumulate in the system. Back then I would have also been buffering with calcium, though now in summer I purely buffer with potassium.

However, the plant may have a calcium deficincy due to lack of uptake due to high nitrates?? I did not see much classical calcium deficiency (cupping of leaves or necrotic spots), but perhaps it was not severe enough for that. I still think K or possibly even P which I have found was very low in my system may have been the issue.

Handy having a horticulturalist for a wife

Hey Matt, you said you are struggling with high nitrates in another thread. Have you found a solution? Mine are off scale - a 1in 5 dilution was still around 80-160ppm

Yesterday, I bucketed out a couple of 100 L and topped up with rainwater. I will need to continue this over several days to make a dent on the nitrate levels though, and add some more salt and keep adjusting the pH up ... I also squeezed in a punnet each of bok choy, celery and white violas (to deter cabbage butterflies). 19 of my 20 towers are planted out with strawberries, rocket, parsley, snowpeas, coriander etc, and the 2 GBs are crammed with plants, lots of lettuce, spinach, beetroot, watercress, spring onions and a small tomato. I only have 25 trout and 5 yabbies in the sysltem. I am at a loss as to what to do until plants can grow enough to sop up the N . Perhaps add a bathtub to grow and harvest duckweed

I would be grateful for any suggestions

Joc,

For a quick temporary (removable) fix check out adding a net bag of zeolite.

http://www.ebay.com/itm/6-LBS-Zeolite-A ... 4897.l4275

I'm going to set up sprinklers on the soil garden (low pressure raindrop types) and run bi weekly 'water changes' until I find the sweet spot in terms of % water change needed to get nitrates down. Its either that or a bird netting denitrifcation tank, though I would rather use the nitrogen than gas it to air.

Long term I'm thinking of getting rid of a system and setting up more earthan style beds and running them from the remaining fish tank. Personally I think a 4m2 planted area (2 x 500L) grow beds running from a 1000L tank with a quoted max of 50 fish will be way too much feed input for the plants to handle.

I'm thinking I may need to clean the grow beds - and thats only after 2 years

I'm running into the need to clean my growbeds. I have half barrels with gravel media. Never did it before. Should I remove the gravel, wash it, scrub the barrels and reuse the same gravel??

Thanks

I was planning on weighing down the media guard, flooding the bed, giving it a good stir and then draining and doing this a few times. Need to strike a balance between moving excess organics and washing away the biofilter. I would also use only aged water (not straight from the tap). I would also run a mulch form through it to get any undecomposed roots out while its flooded.

Cut in half which way?

Depending on how bad they are and what's in the bed it might take different levels of cleaning. Most of the time if you pour a 5 gallon bucket in really fast you can flush a lot of solids out of a grow bed (particularly if it's the round expanded clay balls which like to float). Might need to do this two or three times. I'm not sure with gravel since it won't move around as much you'll probably have to do like mattyoga is saying (I'm not sure about that last part though, what's a mulch form ). No need to remove the media and scrub it though. Having lots of roots in the media also affects how well this works.

whoops should have typed mulch forK.

http://www.bunnings.com.au/fiskars-mulch-fork_p3360619

Barrels are cut long ways See my system here

http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=22925