Food grade plastic?????

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Food grade plastic?????

Postby spbreeder on Thu Jan 20, 2005 12:18 pm

I happen to have 2 Sterilite tubs that would fit into my stand perfectly, how do I know if the plastic is OK??
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Postby friogatto on Thu Jan 20, 2005 12:32 pm

get a TDS meter.
Fill the tubs with RO/DI water and measure the TDS.
Cover tightly and wait 1 - 2 weeks.
Measure again, if the TDS rises it's leaching things into the water and not safe. Of course Saltwater is more corrosive than RO/DI so there is no way to tell except contacting strylite and asking them.
Hope this helps.
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Postby tapper of spines on Thu Jan 20, 2005 12:36 pm

I would go a step further and test for various substances, especially phosphate, after the two weeks are up. That's what I did before installing my 'sump.' If it checks out then it's probably ok.

TOS
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Postby spbreeder on Thu Jan 20, 2005 2:38 pm

Thanks, I am going to contact the company. Do you know of any tubs off hand that are food grade? There are so many companies and types of plastic within each company. What is a TDS meter? Could I test saltwater before putting it in there and after it has been in there for 2 weeks and see if there is a difference?
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Postby friogatto on Thu Jan 20, 2005 2:46 pm

TDS = Total Disolved Solids. It's a way to measure metals, organics ... in water. Unfortunately the TDS meter only goes up to 999 which is much less than saltwater.
Your RO unit or RO water should be under 10 or as close to 0 as possible.
Salt water would give you a reading of --- or 000.
You could take a cup of saltwater that is in the tub and dilute it until the water can be read. But yoru also introducing bacteria and other things with the salt. I would stick with the RO water. It's easier and mroe acurate.
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Postby tapper of spines on Thu Jan 20, 2005 2:48 pm

TDS = Total Dissolved Solids. I'm pretty sure that a TDS meter is actually just a conductivity meter that has a built-in relationship between conductivity and typical concentrations of stuff in water. You don't use it on saltwater, you use it on RO/DI water. If you have an RO/DI filter you should really have one to test the quality of your filtration.

You can test saltwater before and after if you want, but not with a TDS meter. You could test for phosphates and nitrates and the like using the usual test kits.

HTH
TOS
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Postby tapper of spines on Thu Jan 20, 2005 2:50 pm

Ah, friogatto, you beat me to it! :lol:

TOS
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Postby spbreeder on Thu Jan 20, 2005 3:04 pm

You are too fast. I just called rubbermaid and they said that the only containers of theirs that are made with food grade plastic are the containers that are actually made for food. They are all too little, hmmmm a 1 qt sump. I sent an email to sterilite we'll see what they say. Denise
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Postby spbreeder on Fri Jan 21, 2005 10:34 am

Ok, I don't mean to sound dumb, but does everyone check the container they mix and store saltwater in? I never did and no one ever mentioned to me to do it. Just wondering if I am the only one who has never done that. Denise
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Postby BraenDead on Fri Jan 21, 2005 10:41 am

Most plastics are produced from plastic beads which are highly pure and should not be corrosive. Inmost cases, I think you will be fine as long as you check the type of plastic the container is made from (should be marked on the product or the packaging) and make sure it is safe for saltwater (which 99% of plastics are). Other than that, make sure you wash it off and it should be fine. I can not imagine any plastic injection/molding process which would add impurities or anything of concern.

Bob
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Postby Brad_608 on Fri Jan 21, 2005 11:16 am

agreed :D
I'm unemployable Yeah
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Postby MattK on Fri Jan 21, 2005 2:44 pm

I've heard from a lot of people that the "Brute" branded trash cans are safe. At least that's the type I'm using to store my makeup water in.

Matt
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Postby boonbee on Fri Jan 21, 2005 6:16 pm

I have brute cans too. You can get them at home depot and you can buy separate wheel caddy so you can move the containers more easily. N
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Postby Mark on Fri Jan 21, 2005 7:12 pm

`Brute' can here.

I always heard that Brute in White, Yellow, or Gray were safe [so says online legend]. HD had Gray, so I've got a pair.

Dunno if that helps
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Postby spbreeder on Fri Jan 21, 2005 7:21 pm

Thanks. I'll head there this weekend if the roads are clear.
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