Could air in the system cause this problem? Yes, it is. The water turbulence, is caused by a lack of backpressure. What type of heads do you have? Impacts? Could this be caused by a slow leaking head? Yes, it is being caused by water draining out of the zone. One that is lower than the other heads and the valve? Yes, that is how a siphon works, and drains a zone. You need to find out which head is failing to pop up. Some heads (impacts, and some rotors) allow more water to escape before they are fully extended. This means, that the zone then uses more flow, than available, and never developes enough back pressure to fully lift the heads and clear the air from the lines. I would replace all the heads on the zone first, after I was sure there are no leaks or defective heads. Second is the valve.

Oh my. What is a passionate rose lover like you doing in that glacial hell hole? Reading about your endeavors has exhausted me and I haven't even lifted a shovel. I admire your grit and determination, but would love to see you rewarded with thousands of blooms on your rose bushes for all your hard work. I bet they could use engineers in zones 7 to 10!

Hi no-green-thumb!~You really do have a lot of hidden potential. It has been a long winter; I am in IL, so I know how different winter and spring can look! Still waiting for plants to "pop" here, although a little green is finally peeking through. I did a paver installation in my landscape construction class. They need a gravel base, and proper grading. Their installation makes them more impervious to water than flagstone, which will heave slightly, so IMO flagstone is not the best choice for a patio right next to the house. They tend to be somewhat expensive. BUT the cost of installation of your existing patio included the flagstone itself, which you still have and can re-use, so don't despair! We have a flagstone patio in the far corner of my backyard, and I think that could look lovely with your forest backdrop. It is really not expensive to do, just labor intensive. Many nurseries have staff that might be able to do the job or recommend someone, so if DIY is not an option, you should get several bids before proceeding. Or, this is what I would do if it was MY yard... I think it would be best if you had a deck installed; one without steps, just a walkout that extended from the corner all the way to the purple fence to the left of your ac unit. Replace that panel with six foot cedar fence panels, to hide the AC from view. To add interest, stagger the fence heights. The deck would have an octagonal cut-out for the tree, and low wide steps to the flagstone path connecting it to the cement patio. The flagstone path would be wider at the steps and narrower towards the patio, but it would be at least three feet wide, four feet would be better. I wouldn't touch the stone edged bed of hostas and ferns, except to maybe trench the edge slightly, so that the stones "sink" and are no longer a problem when you mow. I really dig (no pun intended) the natural stone and flagstone combination. However, the wooden deck and cement patio are both more practical surfaces for grilling and eating, more sure-footed. I agree that the cement patio is one logical place for your existing grill. Since that was also expensive to install, why not re-use it? Have you seen these type of gazebos, they're a great way to define the eating area from the lounging/bar area closer to the house? They are designed to be taken down and stored in the winter. Here is a link that might be useful: Gazebos

I just bought a package of 3 bleeder caps, varied sizes, in HD today. $2. A helpful employee found them after a bit of searching. They were by the valves. Two Qs: (1) Should the cap seal by just hand tightening, or do I need to use pliers? (2) There are three gaskets, how does one determine which one to use? Should it be tight enough that I have to push it in to seat it in the cap? Thanks.