Will have a read, thanks
I was just thinking, not wanting to be controversial as this is all new to me so learning, if regular water changes are done and seachem added then there wont be a concern with ammonia, nitrate and nitrites as the water is replenished regularly
if I just remove and replace most of the tank water every week, it guarantees healthier water conditions!?
Based on last quarter the hardness level states the value as slightly hard and Ph values are as follows
Average7.53
Maximum7.79
Minimum7.35
As well as the point
@kwi made, which does happen, and the first thing we check when something seems wrong is to check the water parameters - but when changes are made, such as when you decide to replace the gravel, that is often the cause of what we call a mini-cycle. You lose a huge chunk of the beneficial bacteria in one go, ammonia and nitrite levels spike, it requires daily water changes for a while to keep on top of things, and testing the water lets you know where you are in that process, and when that crisis has passed and you can resume weekly changes again.
It's also a matter of routine and experience, and things like stocking. By the nature of keeping cichlids, you have to keep the tank overstocked to handle aggression and territorial issues, which gives you less wriggle room in terms of water quality. When things go bad, they can go bad fast. At this point, you can't tell whether weekly water changes will be enough, it might work out that in terms of your bioload and filtration that your particular tank, with your water (tap water in some areas has higher nitrates than others, for one thing) that yours would need to be twice or even three times a week, no one can tell you how often it will need to be done in your tank, not without some regular testing to establish a baseline.
I'll use my tank as an example. I don't usually test weekly, only because the tanks have been established for a while and I've got a pretty good handle on it now, I over-filter and understock, and maintenance is always managed. But I keep this one tank understocked, with excess filtration;
And a weekly change is usually all that's needed when stocking is as it is right now, and you see how densely planted it is, which does a lot to maintain water quality, and isn't usually possible in a cichlid tank. But when I have baby fish growing out in there and the bioload is heavier, it needs changes 2-3 times a week to keep the water quality good.
But when I first set up the tank, it mini cycled for four days, needing 75% water changes daily for those four days, and daily testing so I knew when the cycle had passed and the tank was stable again. I couldn't assume it was okay without testing, because anytime ammonia or nitrites are above zero, fish are being harmed and can be killed. Then another time I added some cheap root tablets (plant fertilisers) that released too many nutrients into the water column, spiking nitrites. Daily 75% water changes and testing daily for 17 days to keep on top of that, and it still killed one of my fish before I discovered the cause and removed as much of the fertiliser as I could, then a few more days of management before it settled again. The fish didn't show signs of stress either, the only reason I knew nitrites were high was because of testing the water, by the time fish show signs of ammonia or nitrite poisoning, it's often too late.
If any fish get ill and you medicate them, some medications can crash the cycle, meaning you need to test the water to see how things are and how often you need to water change to manage it. You can't rely on weekly changes to keep the water good all the time I'm afraid. Filters break, fish get sick and die, unforeseen issues affect the cycle and water quality. I'd also say that a good number of the issues people come to the forum for help with stem from water quality issues, it's always one of the first things we ask for a reason, because it's so often the cause of the problem.