Questoion about Hayward Sand Pump Sight Glass and Backwash


May 15, 2017
New York
Hello All,

Been using this sight for awhile but I have to ask a question that has probably been asked three thousand times.

I have a Haywood Sand Pump S180T It is a year old. I opened my pool a few days ago and noticed the following.
#1 When the handle is on filter there is no water filled in what I think is called the sight glass (Bubble where you see dirty water when backwashing)
Couldnt remember if there should be water in this glass when doing normal filtering, but I believe it was in there last year.

#2 When backwashing, I have noticed some sand coming out. Most of the time, very little. Once there was a lot. Spyder Gasket?

#3 Pressure Gauge has read 0 PSI since I opened the pool but the return was full force. I went and changed the gauge tonight and it now reads 12 PSI but still no water in the sight glass unless I backwash and rinse.

Let me add, there is no sand coming into the pool, so I don't think it is the lateral.

So I guess my question is with the filter and skimmer seeming to work, is it normal to not have water flow through the sight glass when you are in filter mode? And also, should I be concerned about the sand coming out of the backwash.




Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
:wave: Welcome to TFP!!!

1. There should only be water in the sight glass when you are on backwash or rinse or waste modes. Not on Filter or recirculate.

2. I would not think spider gasket, on backwash you are running the water up through the sand. To come out the waste pipe, you would need to have too much sand I think? IDK, never had a sand filter

3. So you had a bad gauge and replaced it ... no question here right?


May 15, 2017
New York
Thanks for the quick response. Yes it looks like a bad gauge. So then I shouldn't be concerned with sight glass? Thanks feel a little better now.

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