Rodi water vs tap

[Oiler3535]

Been in the hobby 2 years now. 1 unexplained mini crash but nothing major. I finally stopped using treated tap water and bought an rodi unit. Just a cheap RO Buddie but figured would be decent. I haven't noticed any differences in my tank, but I bought a tds unit for curiosity. My tap water is between 65 and 70. After the 3 stages of RO, it's 1. After the DI it's zero. I know the 0 is expected. Is the 70 out of the tap and 1 after RO about normal? How high should I allow the other 2 numbers get before replacing media?

 

[hkgar]

The expected rejection rate after RO is generally between 95% and 99%, so would be very good.. Tap after of 70 is very good. IMHO. Mine is 280, but is well water and also after the softener.
Your carbon and sediment filters should be changed every 3-6 months, depending on usage. RO membrane should last 5+ years.

 

[Oiler3535]

The expected rejection rate after RO is generally between 95% and 99%, so would be very good.. Tap after of 70 is very good. IMHO. Mine is 280, but is well water and also after the softener.
Your carbon and sediment filters should be changed every 3-6 months, depending on usage. RO membrane should last 5+ years.

Well, there's no way this DI cartridge is lasting that long. The bottom inch is already turning colour and has only done maybe 30g of water.

As for the others, what ppm would you wait for the output to be before changing. I don't do regular water changes so a calendar isn't going to work. It's 1 now, wait until above 5? 10? 2?

 

[mcgyvr]

Prefilters would be changed based on pressure loss not tds..
Ro membrane is changed when the rejection ratio falls outside a predetermined lower limit..
90% is decent number..

Di stage is often replaced when tds is 2-5 on average...but typically at the same time as the prefilters

 

[Oiler3535]

Prefilters would be changed based on pressure loss not tds..
Ro membrane is changed when the rejection ratio falls outside a predetermined lower limit..
90% is decent number..

Di stage is often replaced when tds is 2-5 on average...but typically at the same time as the prefilters

Thanks. Rejection rate not measurable for me. I just send it down the shower drain.

 

[mcgyvr]

Rejection is a comparison between input tds and tds at output of membrane...measuring waste is not necessary

 

[Oiler3535]

Rejection is a comparison between input tds and tds at output of membrane...measuring waste is not necessary

Thanks. The line between feeling stupid and learning can be invisible at times

 

[hkgar]

If your tap water tds is 70 and post ro tds is 1 than rejection rate is 98.5%, which is very good.

I change pre filters when pressure starts to drop and di when tds post di is 1.

 

[FamilyTank]

Thanks. The line between feeling stupid and learning can be invisible at times

Lol, I love it! We've all been there at some point in life's travels.

 

[rocsec1]

And many people dance back and forth over the line

 

[Timmayyy]

The only time I tried tap water, I got a nasty algae bloom. It must have bee the high silicates.