I've heard talk about increasing the ferts dose till the nitrate levels raises to 20ppm higher than the base line? Have you heard about this?
Sounds a load of rubbish to me!
Firstly we have no reliable way to measure nitrate levels on our tank water that accurately, so in reality we'll never know our nitrate levels unless we send a sample off to a lab for testing. Secondly I don't think plants particularly care what the long term equilibrium levels are, they'll adjust their function to suit. I've had tap water tanks with EI dosing that must have had very high long term equilibrium levels of NO3, and I've had tanks where almost all of the dosed NO3 is used up by the next dose day.
It's why I've never really understood the ongoing arguments between lean vs rich dosing, as both system tends to grow plants just fine in either scenario.
I've always looked at my TDS as a guide?
As do I, but not as any type of guide or assistance to fert dosing. I'm a huge believer in tank stability, so I want my TDS to be exactly the same every day and every week, as one of a number of indicators to tell me I'm achieving that stability.
I'm starting the week after a water change at 120-150TDS raising to 280 -320TDS by the end of the week, but I've been told this isn't a good way to know if I'm dosing enough ferts?
Surely there is something else going on there then, as that seems way too much of a TDS increase to be ferts alone? Do you have Seiryu stone or similar in the tank?
How do I know I'm dosing enough for my plants and what's too much?
You have a few options:
You can simply calculate it (use the IFC Calculator), and strictly dose what you calculate, and then have faith in those calculations - then you inherently know there are enough ferts in the system because you have ensured there are in your calcs (by ensuring an excess). This works unless you know you are dosing intentionally very lean, in which case you know you are already sailing close to the wind, and risk any one of those ferts bottoming out.
You can use test kits as an aid - now I know they are generally disliked on this forum, but I think they are sufficiently useful when used within their know accuracy (which is pretty coarse). For example I never use them to work out a absolute numerical level of an element in the water, all I want them to tell me is if I have a 'a lot', 'a little' or 'none'. Say with Iron for example, if the sample is dark purple I know I can dial the iron dosing back a fair bit, if the sample is perfectly clear I know the iron is bottoming out, if it has a little tinge of colour just before the next dose, I know I'm around about hitting my mark.
You can look at the plants. Darrels Frogbit Index (I refuse to reference the evil that is Duckweed) works very well, and I use it as an additional aid on my low tech tanks. On a high tech tank it can be too much of a lag - i.e. by the time you've spotted the change in Frogbit leaf colour, you can already get stunting and algae on other plants, which for me is too late (I'm for prevention rather than cure). On a low tech tank, that's not an issue, as the Frogbit, (with its free access to CO2) is usually fastest to react anyway.
No, CO2 is something we can fairly accurately establish the levels of in our tank via drop checkers or pH meters, so we don't want 'lots' we want 'just enough' to hit our target. I'm no longer an advocate of 'lots of CO2', especially in a tank with livestock (if its just plants, fine blast away).
With the exception of some more difficult plants, I don't think the absolute levels of CO2 is always all that important - more important is both the short term (with the individual lighting period) long term stability of that CO2, which most plants will eventually adapt to.
Definitely not - light is both the saviour and the devil. We can't grow plants without it, but too much of it, and we get nothing but problems. Light is the tanks accelerator pedal, so the harder you push it, the more strain you place of the rest of the system, and to more finely you need to tune the CO2 and fert dosing, CO2 application, flow and distribution etc etc to avoid problems. Take your foot off the gas by turning light levels down, and everything suddenly has much more wiggle room for error and adjustment.
Balancing light levels for the tank is in my view mission critical for achieving clean, algae free plant growth. Most people use far more light than necessary when they can have a much easier time of it dialling the lights down and getting slower, cleaner plant growth.
Which is just one of a number of prescriptive dosing methods - great for the beginner, as it's painting by numbers, and has worked well for thousands of tank. Eventually though, most aquarists will learn to dial EI down to levels they know suit their individual tanks.
Meh! Where's the fun in that?! lol
I understand what you are referring to, in that lower fish numbers means lower organic waste, and that make life a little easier for the tank system - which is a fair approach.
Beyond that though, I reckon there are two types of aquarist on this forum; those that have fish to make their planted tanks look good, and those who have plants to make their fish tanks look good - I'm firmly in the latter camp!
