Anyone Using Rexolin APN from HPC?

[Allan Asis]

Any idea how much Rexolin APN powder (in grams) were dissolved in typical 120mL bottle of Rexolin APN from HPC?

It's described in website as below:

"An ideal mixture of all chelated nutrients mentioned above containing 5.8% iron, 2.3% manganese, 1.3% zinc, 1.05% boron, 0.25% copper, 0.24% molybdenum and 0.03% cobalt - Note: Rexolin APN mix (100g) is unstable in humid environment like Singapore. Hence, we have the same Rexolin APN in 100 ml liquid form priced at $ 12 per 100 ml - See more at: http://www.ecocityhydroponics.com/rexolin-apn.html#sthash.HNhyGlvX.dpuf"

It does not imply how much really so I asked via email. I was told it's 100g. Ok Is it possible to dissolve that much in a 120mL water?

I did try to measure (Fe using Sera Fe Test Kit) via dosing a certain amount in a known quantity volume of water and expected a much less value than I expected. Several tries yield me consistent result which tells me it contains only 5-10g.

Now as consistent as the result that I get, I'm not really sure how accurate Sera Fe kit is so If anyone really knows I really appreciate if can help. Many thanks.

P.S. I again asked the late Dr. Mallick's daughter to help check for me the actual concentration, waiting for reply.

[vinz]

Frankly, I think it will be really hard to dissolve that much of any solid in that amount of water. It's almost 1:1. 5 to 10g sounds more like it. If you can get Rexolin APN powder, you can make your own solution.

To make a 10% solution, dissolve 100g in 800ml of distilled water. Once its completely dissolved, add distilled water until the entire solution is 1000ml. With that, every 100ml dose is 10g of APN powder.

[Allan Asis]

Thanks Vinz.

I tried (not Rexolin APN) but similar product, EDTA Fe which is just iron, no trace. It's very soluble. I put it 100g into a 100mL of water. It did dissolved fully. Some other compounds do not. K2SO4 the best I can mix without residue build up is 5%. CANO3 I was able to dissolve 40% before I start to see residue that cannot dissolve.

by the way I cannot source out Rexolin APN powder form here in Singapore and Singapore Hydroponics claims they cannot keep it stable probably because it's extremely hygroscopic. And that's probably the same reason why it can dissolve so easily.

In any case, I just dose it at around 1 drop per 20L 3 times a day. It didn't give me problem with plants. I guess a presence of trace will do, does not have to be in abundance. I still use EDTA/DTPA as main source of iron anyways.