Machine feeds

[Ca++]

Any experience with feeds that don't need shaking? Or that do?
I know a few people have used auto dosing kit, and wondered how they went about shaking the bottles, or not. I did once have a feed that said it couldn't be machined. I know the ionic range are not happy, as they use black gunk, that will settle. I chucked in a pump, and it was like a gunk magnet. I'm sure other people have experiences to share. Floranova is gritty, for instance. So too abrasive for many delivery systems.


I have been looking at 2L pop bottles. Making a stand, to have them inverted. Then swapping the cap (which is now pointing down) for one from a smaller bottle designed to drink from. The one's with a nipple that can usually be resealed. This nipple could offer a hose attachment point, for an external pump to send the feed back to the top of the bottle. Get is swirling a little, and the bottles shape should see everything make it's way back to the pump. It's my best idea yet, but I feel there must be others that work for people.


I;m also wondering about tank change intervals. I know some feeds may not actually need one. Others may get a bit toxic, topping up elements that might not of been used. I know the standard advice is two weeks, but there is work towards just replacing what is needed being done. I just don't see the full figures.

 

[Orange's Greenhouse]

The usual salt fertilizers (Jacks, Hakaphos etc.) dont need agitation. You dissolve fully (stock solutions of 10 % or more are possible). Sometimes they have a bit of residue but that can be filtered or ignored and cleaned out when the reservoir is scrubbed.

With organic fertilizers you won't get solutions. They are all particles that get broken down by microbes. If they were dissolved it would be salt.

Recirculating systems are difficult. Some elements such as nitrate and phosphate are fully absorbed very quickly while calcium is absorbed much slower and accumulates. If you replenish with the same solution every time it can become toxic. Adjusting pH also adds significant amounts of a specific nutrient.
It's simpler to change out the reservoir every now and then. Measuring the elements and only replenishing what is required is too expensive unless you run 10.000+ plants.
I attached a review article that gives a good description of the topic. If you want to tinker that would be fun and engage you a few years.

 

[Douglas.Curtis]

Air lines are excellent at agitation

 

[Ca++]

@Orange's Greenhouse
I'm topping up my F&D each day, after 20% has been used. It's strange to think a tank change will mean 5x more N P K will likely be available that day. It's never been a problem before. Learning can be dangerous
I'm in a high calcium area, so that might be the guiding reason I should do a change.

Thanks for the reply, it was useful.
www.actahort.org is new to me. I'm looking for the PDF there now, to get an alternate file type.

@Douglas.Curtis
The airline is quite easy isn't it. That could be useful. I guess a bottle tipped to get one corner lower, could be enough with many feeds. I'm really fond of ionic though, with it's simple 'one bottle' for grow, and one for bloom, approach. It's fully chelated though, with humic products. These cause suspension issues.
If Orange Greenhouse is totally on the money, then an airstone would be ample. I have little pumps that fit through the neck of 5L bottle tops. Actually shaped for the job. So it seems a purely salt feed, would easily stay as a solution. I know the shop has to turn the bottles they stock periodically. Which says the manufacturers are not convinced about them standing around. It's some years since I had a bottle stood long enough to get gritty though. Making slushy noises as you swilled it.

I don't quite feel settled yet. It would be nice to hear of a manufacturer, saying their liquid feeds are okay to stand about.
I can't get a reasonable powder unfortunately.

 

[Douglas.Curtis]

I used GH Flora line and Maxibloom dry powder for over 15 years. I assure you, they'll stay in suspension for months in a res without issues. I don't dump my rez till the end of flower and ran mostly DWC. Bottles of Flora will sit around for a few years without issues, and Maxibloom lasts nearly forever when kept dry.