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This one will require all to pay attention, for once and for all, we are going to put a stop to this 3/8 hose idea.
Just because shurflo put a 3/8 hose fitting on some of it's pumps means little.
The engineers never intended a low psi pump to be connected to 200 feet of 3/8 hose!
Lets take a 45 psi 3.6 gpm shurflo, and take a look at what happens,and how much we lose by crippling our pump with 3/8 hose, OK ? "

The Fluid Flow Calculator

This is your input:
fluid: 10 % solution
fluid temp F: 40F
flow rate GPM: 3.6
pipe size in: 3/8
pipe length ft: 200.00
pipe material: C
These are the results:
velocity ft per second: 6.0462
Reynold's Number: 11699.0414
friction factor fa: 0.0300
friction factor f: 0.0298
head loss ft: 82.3780
pressure loss psi: 36.2326

flow calculator developed by Michael J. Rocchetti PE
Back to the Calculator


"As can clearly be seen, we have just pissed away 36 psi, and we only had 45 to start with!
This is the penalty you pay using 200 feet of 3/8 hose.
Oh, BTW, this is being "kind', for these calculations assume PIPE!
Coiled hose has even more loss!"

"Now, look below, and see what happens when we switch to 3/4 hose ? "
And, this is for a small 3.6 GPM pump too. It gets even worse as GPM is increased.


The Fluid Flow Calculator

This is your input:
fluid: 10 % solution
fluid temp F: 40F
flow rate GPM: 3.6
pipe size in: 3/4
pipe length ft: 200.00
pipe material: C
These are the results:
velocity ft per second: 2.1703
Reynold's Number: 7009.1924
friction factor fa: 0.0343
friction factor f: 0.0341
head loss ft: 7.2616
pressure loss psi: 3.1939

Back to the Calculator

It can clearly be seen that our pressure loss is only 3 PSI using 3/4 hose, compared to 36 PSI using 3/8 hose!
Unfortunately, the hose loss calculator is a free program, and does not have the 5/8 hose selection we recommend as an option, so I had to use 3/4 to make my point.
Bigger hose is better, and it is always better. There is no "debate"
You may be a wuss, and not be able to handle bigger hose, or want to cheap out on buying the large hose reel required to use bigger hose, and that's ok.
Or, you may simply not have the room on your rig ?  All fine and good.
You may not consider the performance improvements going from 1/2 inch hose to 5/8 worthwhile, that's ok too.  We do, because if larger hose speeds an average job up by 15 minutes, it cuts our exposure to the roof cleaning chemicals down.
It also makes our pump have an easier life.