EDTA math

[GuacamoleSalad]

Soapmaking fam! I've started using tetrasodium EDTA to deal with our hard water. Made several rookie mistakes so far but that's what learning is all about, right?

Question: My EDTA is in a solution. Not 39%, and not 50%, no: 35%. Don't ask. I'll make the math easier next time. But for now-- and I guess this question would apply irrespective of the solution-- should I reduce the water I'm mixing with lye in order to account for the water I'm adding with the EDTA? My current recipe calls for 20.5g of EDTA solution, of which about 7g are EDTA and 13.5g are water. Should I add 13.5 fewer grams of water to my lye at the start?

Edited to add: my normal lye solution is 33%.

I realize my numbers are a tiny bit inexact but I had to write a word problem to even understand my question so just trust I'm not selling this soap, I'm still working out the kinks here.

 

[BWt]

I wish I could answer your maths question. However I can possibly point you to additional information on EDTA.
https://classicbells.com/soap/EDTA.asp

 

[GuacamoleSalad]

I wish I could answer your maths question. However I can possibly point you to additional information on EDTA.
https://classicbells.com/soap/EDTA.asp

Thank you! That's a great page. There's so much good information about EDTA on here. I feel sure this question has been answered before. I just haven't been able to find it..

 

[cmzaha]

I always found it easier to simply figure dry edta at a rate of 1% of my total batch weight then remove some of my batch liquid and dissolve the edta add it to my oils. Actually I always use 0.5% EDTA and 0.6% Sodium Gluconate, because I have hard water.

I may cut down when I get moved because we will be putting in a filtration system and water softener. We just received back our water analysis and as suspected our well water is very hard but fortunately no detectable arsenic. Yeah!! That is if I ever make soap again.

 

[akseattle]

That is if I ever make soap again.

@cmzaha , oh hey! don't say that! it makes me sad to think you might fade away from our soaping family!!! I know you've moved and you're moving on to a new and exciting chapter to your life, but, we don't want to lose you!!

 

[GuacamoleSalad]

I always found it easier to simply figure dry edta at a rate of 1% of my total batch weight then remove some of my batch liquid and dissolve the edta add it to my oils. Actually I always use 0.5% EDTA and 0.6% Sodium Gluconate, because I have hard water.

I may cut down when I get moved because we will be putting in a filtration system and water softener. We just received back our water analysis and as suspected our well water is very hard but fortunately no detectable arsenic. Yeah!! That is if I ever make soap again.

Just so I'm sure I understand: you remove some of your batch liquid? Is that your water/lye solution? EDTA is my only additive right now so I don't have any other liquid except oils.

I also have hard water but haven't started using sodium gluconate or anything else yet. Lots of advice flying around out there. What do you like about the sodium gluconate, if you don't mind?

 

[DeeAnna]

I do compensate for the water in the 50% EDTA solution I use. But that's just me -- I suspect most people don't.

Based on the last batch I made, the "EDTA water" is only around 2.5% of the total water required for a batch. I used 33% lye concentration for this batch. If I ignored the added water in the EDTA solution, the lye concentration for my batch would have dropped by about 0.5% -- from 33% to about 32.5%. That's not a lot, so IMO it's reasonable to ignore the added water if you're comfortable doing that.

If you're using a 35% EDTA solution, the "EDTA water" would be roughly 3.5% of the total water required assuming the recipe uses 33% lye concentration.

 

[AliOop]

we will be putting in a filtration system and water softener.

We have been very happy with our Express Water filtration system. We bought just the filtration system without their softening system. I wanted to try that first, since I don't like the slimy feel of softened water. The system was very reasonably priced and does a great job. We do have to replace the filters every six months or so, but it's well worth it! So, we are passing on the softener for now. Not sure if that's an option for you, but you can always call them to ask.

Their website is ExpressWater.com. I do recommend buying directly from their website, and not from Home Depot or Lowes. Customer service is great either way, but they told us after the first system that we bought that they have had issues with small things being missing from systems purchased from the box stores, rather than directly from them (maybe parts being pilfered by store employees?). Anyway, I believe you can get a coupon if you sign up for their emails. It's not a huge discount but every penny counts when you are moving and building a house!

 

[justsomeguy]

We have been very happy with our Express Water filtration system. We bought just the filtration system without their softening system. I wanted to try that first, since I don't like the slimy feel of softened water. The system was very reasonably priced and does a great job. We do have to replace the filters every six months or so, but it's well worth it! So, we are passing on the softener for now. Not sure if that's an option for you, but you can always call them to ask.

I bought the same system. With a permeate pump added in to reduce the amount of discharge water.

Their website is ExpressWater.com. I do recommend buying directly from their website, and not from Home Depot or Lowes.

Got mine from Amazon. No issues with missing anything.