Backyard Aquaponics
A place to discuss aquaponics

For those that have big ap systems, how much water do you have to add on a daily basis and how big is your plant growth? I've read that larger trees can take up 30 gallons a day. I know we don't normally grow trees, but I've seen pics of Ruperts' basil!

I replace very little in my 6000l or 1500Gal system. Maybe 200l or 50Gal per month?

I don't put much water in my system. Can't remember the last time I ran water in it from the tap. If it rains for a couple of days I divert water from the shed roof. But my system can drop 10000ltrs and not make a big difference.

I replace ~50 ltrs/day the fish are thirsty
water body of about 4000l

About 10% of your tank volume... would seem to be the average through summer... especially with a growbed full of plants...

10% Rupe where your leak ????
I would be using about 30l a day in 3300l system so that's about 1% top-up per day.

I have heard it said that a sq mtr of water will evaporate 2000 ltrs in a year .
So a vertical head of 2mtrs or 2000mm will be lost to evap, with out prevention per sq mtr
of surface area.

Prevention is reducing the wind factor stripping the water.

well my tank does have a lid on it so i sure that helps to reduce loses. I know if i run the water fall into my pond I lose heaps both through the stone soaking it up and the extra surface area of the water. Yes I agree with your evaporation factor c1 but the shallower the water the faster it will evaporate due to higher temperature gain/lack of heat sink i would have thought.

looks like im the odd one out here as i was adding about 10ltr a day in the hot weather in a 200 ltr fish tank
so my % is a bit higher than others
but then my system is all above ground too

Smaller water bodies will heat quicker, and by larger temperature graduations than larger volumes Mal... and suffer evaporative losses correspondingly...

With my DWC experiments I have seen 6 banana pepper plants consume 25 gallons of water in one hot humid day.

There are many factors involved. Heat may be one factor but relative humidity is probably even more important. If you are in a dry breezy climate, the plants will have to transpire more to keep some humidity around them while in a humid climate they only use as much water as they need to replenish what they loose. Some plants waste more water than others. And then some shade cloth can keep a system from heating up as much during the hot summer. Covers over fish tanks can reduce direct evaporation but don't seal things up too tight or you won't get good air exchange. Aeration is needed and often the price is evaporation.

Unfortunately I can't really say exactly how much water I top up since I have installed float valves in my systems to add water automatically when level starts getting too low. I especially like this method since you don't have to worry about forgetting and running the hose into the tank till it overflows and you also don't need to worry about the hose siphoning out the tank if you leave it in when you shut it off.

It is important to get float valves of decent quality though as the really cheap pet store ones I originally had tended to fail and overflow the system. I'm currently using the mostly plastic float valves for topping up stock water troughs. I have them installed in three different systems.

That's what I've been considering on using for a bigger system. I was wondering about how much would trickle in and how quickly the chlorine would dissipate from it if I had it on the fish tank. If it allows tap water into the top of the fish tank and I pump water out from near the bottom of say a 100 gallon tank, the water should have enough time to dissipate the chlorine from the new water before going to the growbeds, right? I'd assume it would dilute with water already in the FT some too.

First, make sure your water only has Chlorine and not chloramine. Second, you want to let the system get well established before you start exposing it to any chlorinated water. Many old timers here get away with topping up with un aged chlorinated water but it is usually a really bad idea for a new system to top up that way.

You might be better off having a barrel that you fill with tap water so it can air out and attach the barrel to the AP system with the float valve and top up from the airing barrel.

Yeah, but I was trying to eliminate the need for and extra float and middleman tank.