Hi everyone. I'v dropped a few comments here and there about myself really hot nutrient solutions eg EC + 2.6 in RO water. I'ts a bit misleading as I dont maintain a steady EC but rather let it weaken until I consider it "spent" and then chuck it away. Anyways this is a technique that my "guru" showed me many years ago and it's never resulted in horrible deficiencies of extreme fert burn. Also, theres no flushing and I've enjoyed good consistent results for many years. Here we go...
Consider this scenario - I make up 100L of nutrient solution at full strength EC = 2.0'ish. Every day I top it up with fresh water (no nutrients) and adjust the pH. The nutrient strength drops a little. I repeat this until I've used 100l of top up water (same volume as the initial solution) and then dump it (all 100L) and start again. I was told that if the EC at the time of dump was less than 1/2 of the inital reading, then increase the strength of the next batch. Keep doing this, unitl the slightest tip burn shows and then back off a toutch. Because this technique discards so much water, there is generally no need to flush, the flush is continual.
When I queried this - WTF, I though consistency in ec values were key? he replied - Think about what's happening inside the pots, the nutrient values are just an indicator. You must think about the root zone and insisted that values will be more stable with his technique, he also added that deminishing nutrients encouraged strong root development, which acts as a massive energy reserve for when your plants bloom.
He was in Adelaide - The water was absolute turd and has an EC of about 0.7. Most of the reading was due to sodium, and because the plants didnt use it much, it built up in the solution. If you filled a pot with water with ec 0.7 and boiled it down to 1/2 the original volume the ec would be 1.4. It was very similar in the nutrient solutions, if the plants used 1/2 of the nutrients, the sodium content was about double that of at the start and is really getting out of control, time to chuck it.
Now my water is great EC =0 (less than my meter will read anyway) There is none of that sodium build up shit, so my nutrient solution drops far below 1/2 of the original value before I chuck it. NOW I make up my nutrient solution at full strength, add fresh water every day and dump it when the EC reaches 1.0. I know my plants will use the entire volume of my res in 3 days (dump time), so if the nutrient value is less than 1.0 after 3 days, Ill make the next batch stronger. During the last run, I maxed out the EC at 2.6 and after three days it was 1.1, so the next batch was mixed weaker.
Not many have adopted this technique over the years, most shake their head. The few that have taken it on have had nothing but positive things to say.
There are many ways to manage nutrient, this is just one system that remains in the shadows so I thought I'd put it out there. By no means am I claiming that its the best, its just worked for me.
Does any of that shit make sense?