No Suction with DOS and John Guest Fittings

[LiquidSpace]

I bought this: https://www.bulkreefsupply.com/1-8-...=12515&indexName=brs_prod_m2_default_products

And I bought this: https://www.bulkreefsupply.com/blue...D=9876&indexName=brs_prod_m2_default_products

I’m trying to connect them to my DOS. The fitting is screwed on tight. The RO tube is completely inserted into the DOS unit. What am I doing wrong? Didn’t buy the wrong stuff?

 

[landlubber]

i'm away from my tank at the moment and could be wrong on this but i'm inclined to believe the clear tubing that is included with the DOS has a considerably larger (maybe even double) interior diameter that typical RO line and its probably causing you issues.
have you tried to draw fluid through the normal lines that come with it?

 

[A_Blind_Reefer]

Did you cut off the tip of the original barb?

 

[Dburr1014]

I bought this: https://www.bulkreefsupply.com/1-8-...=12515&indexName=brs_prod_m2_default_products

And I bought this: https://www.bulkreefsupply.com/blue...D=9876&indexName=brs_prod_m2_default_products

I’m trying to connect them to my DOS. The fitting is screwed on tight. The RO tube is completely inserted into the DOS unit. What am I doing wrong? Didn’t buy the wrong stuff?

That is the right stuff you bought.

1) did you cut the end tapered piece? Have to cut it down.

2) did you put some thread tape on the threads? It helps.

3) did you make sure the thread is tight?

4) how old is the roller hose? Did you see if it has any pin holes?

 

[LiquidSpace]

That is the right stuff you bought.

1) did you cut the end tapered piece? Have to cut it down.

2) did you put some thread tape on the threads? It helps.

3) did you make sure the thread is tight?

4) how old is the roller hose? Did you see if it has any pin holes?

Number 2 did it!

So might as well ask another dumb question to save time. This was used for dosing in a much smaller aquarium and now I’m using it for AWC. When calibrating it do I need to calibrate with the length of tubing that will be used for the AWC or can I do that with a shorter tube?

 

[Dburr1014]

Number 2 did it!

So might as well ask another dumb question to save time. This was used for dosing in a much smaller aquarium and now I’m using it for AWC. When calibrating it do I need to calibrate with the length of tubing that will be used for the AWC or can I do that with a shorter tube?

It doesn't matter the length of tubing. Just make sure the liquid is all primed the whole length of tube before calibrating.