GrahamC

http://www.xrite.com/custom_page.aspx?PageID=77&Lang=en Tests your colour vision ... and if you do badly, you'll know why you can't read those test strips! I scored 42

I'm frugal .. I only give them the ends with the stalk on them!

Your situation is a little different from most in that your tank has been running since Xmas with no biological filtration but just the filter, and the filter material has been in another tank? So, you started off with an unknown proportion of microbes when you returned the filter material and sock that create nitrites and nitrates. So, blueether might be right in that you might be forming nitrates so that's why you don't see the nitrites. You've seen your ammonia rise from 0 to .25 to .50, so I'm guessing that it will be another week before you start to see nitrites and the ammonia fall. Keep up with the PWCs

I thought blanching was done so that the courgette sinks. Otherwise it floats. I thought the advice was to feed a small amount, and then remove it after a day or two so it doesn't pollute the tank though I've tended to leave it in till it's gone.

the only way you could be removing too much to cause stress is if the new water differs substantially from the old, but since you're nearly doing daily PWCs, it is likely the new and old water are much the same apart from the ammonia. Stress occurs when the new water differs too much in osmotic pressure and temperature. When I had this issue I was doing twice daily 50% water changes. And the bugs that process the ammonia are not materially found in the water but on surfaces and in biofilms so you can't remove them with water changes.

So, this would confirm that you do have ammonia in your tank which is therefore not cycled yet So, better keep up with the daily PWCs to protect your fish. It doesn't really matter what the numbers are as you want 0 ammonia.

I need some matai floor boards ... but I guess no one is burning those!

The National Aquarium is a bit far to come to meetings! Wonder if the Wgton club is still active ... their website is only giving last year dates.

http://www.stuff.co.nz/national/3729299/Health-warning-on-burning-treated-wood :slfg:

I would also think you should have some nitrites by now. What you can do is test your tap water against the ammonia kit. And then test your tank water again using the tube in the nitrite kit and compare them side by side. If you're not too far from the LFS, you can also ask them to test your water. If they have them, Seachem ammonia alert is a better purchase i think as it tells you free ammonia and not total ammonia.

It doesn't matter what system you use. If you remove less nitrate than is created, you'll get nitrate creep.

Heat pumps can have difficulties in the extreme colder regions of NZ Being a greenie at heart, I'd be very reluctant to install a coal fired burner.

Luckily many of us don't live where water usage is metered

The two siphons most commonly used in aquaponics for automated water changes are the bell siphon, and the loop siphon. The loop siphon can be easily modified to do a partial water change, but I'm not clear if a bell siphon can do this with 100% reliability. You would need a siphon break, and that would be the issue .. you certainly don't want the whole tank emptying!

Heat pumps are normally sized to heat the room they're installed in .. not the whole house. I'm looking at putting in central heating now, and there's a heat pump already installed. I'm thinking water radiators powered by a gas burner might be the most effective for us. You can also get oil based heaters that use waste oil. For more "fuel" for a wood burner argument see http://www.consumer.org.nz/reports/heating-options/fuel-prices-compared

The mathematical model above assumes that the water being removed is all old water, but if you have a continuous water change system, you may be removing some new water with the old water. It will still be an exponential decay process and the difference this makes may be negligible

Yes, both ammonia and nitrites need to be 0. Yes, don't need to measure nitrates if you do the regular water changes.

It's a bit more complicated as there is an unknown rate of nitrate generation in the tank.

It sounds like you have the nitrogenous wastes covered better than most of us with your automatic water change system. Theoretical question, is there any possibility that you might be adding heavy metals faster than the plants can cope with removing them?

This is like one of Zeno's paradoxes ... you can't do a 100% water change thru infinite partial water changes. But of course you can. You have to look at why you are doing the water changes for, and whether the frequency of those changes achieves the desired effect.

I'd go for the wood too. Is there any position on burning wood for heating in Dunedin though? Some councils are trying to reduce particulates in the air.

Caper, do you have fish in that tank right now? Not only do you have to wait for ammonia to be 0, but also nitrites. Yes, there are different types of java fern.

My suggestion was for those who are less adept at math. I have a wireless meter that wraps around the main power cable to my mains meter which gives me instantaneous power consumption for my household. I bought it a few years ago now. See http://www.centameter.co.nz/ I presume to work out the consumption for a tank, I'd wrap the sensor around the lead to my trailing socket. But as far as I recall, it won't tell you monthly power usage, just instantaneous. So, something that can integrate over a whole month might be better. The centameter is useful for telling you if you have a load in the house that you weren't expecting. It's good enough so that I can see if someone is using the microwave in the kitchen while I am in the living room. Or, if someone left a heater on somewhere.

I used hovmuller's calculator just now to estimate my power consumption for the heating, and it came to $6.90 which is pretty close to my ball park guess of $7.20 How about adding a switch for those using Fahrenheit ( USA )? And also some formulae for lighting, filtration and pumps to get a total power consumption calculator?

Here's a rough stab at it. I run a 100Watt ( or 0.1 kW) heater in one of my tanks, and it seems to be on at night, and off during the day ( near a window with sun ). Assuming that it runs all night, that's about 12 hours. An average charge for electricity is 20c per kWh ie. 1000 Watts over an hour. Assuming 30 days, then 30 * 12 * 0.1 * $0.20 = $7.20 per month to run my 100W heater half of every day for a month. Now all you have to do is add up the other things like lighting, and filters. And in winter, some of that heating is going into the room as well