How can I make water changes easier?


A reader asks for advice on best ways to keep his tank healthy for keeping discus.

I’m buying a 240 l tank in which to keep discus. I’ve read that a 30% weekly water change is recommended, meaning 80 l weekly or 12 l daily on a tank of that size, and I’ll need to find an easy way to do this. I have looked at the Python syphon, but I would not trust my mixer tap to maintain a constant temperature. Do you have any recommendations?

I’m also looking at buying a second aquarium for a breeding pair of discus. From what I have read, the Juwel Lido 120 seems to be suitable, but a couple of things concern me. Is the supplied Juwel Bioflow filter M sufficient or will I require an additional filter? Will the Juwel Multilux light be too bright for discus – and if so, can I replace the bulbs for a more suitable option? Please could you advise?


Jeremy says: If you used a Python syphon on a daily basis, at just 12 l of water a day you’d only be changing around 1/20th of your tank’s gross volume, so even if the temperature is a bit out, it shouldn’t matter. But remember to put the right amount of tapwater conditioner into the tank before you refill, so that you’re not exposing your mature filter to chlorinated tapwater. 

Inline, pond dechlorinators could also make a handy solution for providing tank-ready water from the tap, through the Python. 

You could also consider using RO drums for water changes. A 25 l drum would hold enough for two days’ worth of changes. You can get handy little pumps these days that fit inside and pump water up to the tank, topping it up. You could use RO water in the drums or tapwater that you could bring up to temperature 24 hours in advance by dangling a heater in the drum. Another option would be to use an old fish tank, reservoir or a small water butt to fill with cold tapwater, again dangling a heater inside for a day or so, and then you’ll have ready water on the day you want to do the change. You could even use a pond pump and pond hose to pump 80 l of water out of the main tank, through the back door and into the garden, and then use the same pump and hose to pump the new water back in. This is quick, easy and will save strain on your back! 

The Juwel Lido filter will easily cope with a pair of discus or fry, although most people opt for air-powered sponge filters in Discus breeding tanks so that the sperm isn’t blown off the eggs, and the fry aren’t sucked into the filter later on. Tank bred discus shouldn’t be bothered by bright light, although if you want it dimmer, consider having the tank lights off, with ambient room light being just fine. But to be honest, if you decide not to use the lights or the filter, a systemised aquarium like the Lido may be overkill, with a bare tank and sponge filter being a much more economical choice.