Sumi Soaker R-Wide vs. Mark II: Which Model to Choose

If you've decided the Sumi Soaker is the right overhead irrigation system for your operation, there's one more decision to make: R-Wide or Mark II. These are the two Sumi Soaker (Sumisansui) models we carry, and while they look similar — both are flat polyethylene tubes with laser-cut holes that spray a fine, rectangular mist — they're built for different growing situations.

Picking the wrong one usually comes down to a mismatch between the tube and your water supply. The good news is that the decision is straightforward once you understand the two things that actually drive it: how much water pressure and flow you have available, and where and what you're growing. This guide walks through both.

If you haven't read our overview of how the system works, start with What Is the Sumi Soaker. Otherwise, let's get into the comparison.

Here's the decision in two sentences. Choose the R-Wide if you're irrigating open field beds and have decent water pressure (15-29 PSI) and flow. Choose the Mark II if you have low water pressure (like a gravity-fed tank or low-output well), you're working in a greenhouse or tunnel, or you need the spray to clear taller crops in the field.

That covers most growers. If your situation is more nuanced, keep reading.

The single biggest factor separating these two models is the water pressure each one needs to operate.

The R-Wide is rated at 0.20 MPa — about 29 PSI — and operates in a range of roughly 15 to 29 PSI. It's a high-performance tube that needs that pressure to push water out wide. Give it enough pressure and it throws a fine mist up to 33 feet across. Starve it of pressure and the spray width collapses: at around 22 PSI you're down to about 26 feet, and at its 15 PSI minimum you're only getting about 12 feet of coverage. Below 15 PSI, the spray breaks down entirely.

The Mark II is built for low pressure. It's rated at just 0.08 MPa — about 11.6 PSI — and will operate as low as 0.02 MPa, which is under 3 PSI. That's a remarkably low requirement. It means the Mark II will run off water sources that can't come close to powering an R-Wide: gravity-fed header tanks, rain barrels on a stand, low-output wells, or municipal supplies that have already lost most of their pressure to a long hose run.

This is why the question "how much pressure do I have?" matters so much. If you don't know, our Water Supply Check will walk you through measuring it before you buy. It's the most common reason a grower ends up with the wrong tube.

Pressure is how hard the water pushes. Flow is how much water you have, measured in gallons per minute (GPM). The two models have very different appetites.

The R-Wide is thirsty. A 100-foot run at full pressure demands about 12.7 GPM. A full 330-foot roll needs nearly 42 GPM — far more than any garden hose can deliver, which means long R-Wide runs require a dedicated mainline or pump. If you're going that route, our mainline pipe sizing guide walks through how to size your supply line so it can actually feed the tube.

The Mark II sips by comparison. A 100-foot run needs only about 3.6 GPM, and even a full 330-foot roll draws under 12 GPM. This low demand is what makes the Mark II so forgiving — it'll run off almost any garden hose at almost any length.

Here's how the two compare side by side:

The practical takeaway: the R-Wide needs a serious water supply to run long beds, while the Mark II can run long beds on modest water. If your water source is limited — whether by pressure, volume, or both — the Mark II is often the only one of the two that will work at all.

The two tubes don't just differ in what they need — they differ in what they deliver.

The R-Wide sprays low and wide. Its spray exits at a shallow 35-degree angle, throwing water outward up to about 16 feet on each side — 33 feet of total coverage at full pressure. That's wide enough to cover eight 30-inch beds from a single line running down the center pathway. The trade-off is that a low, flat spray is easily blocked: a tall crop, a row cover, or shade cloth on either side will intercept the mist before it reaches the outer beds. 

You can solve this by elevating the R-Wide on risers — vertical posts about 3 feet tall that lift the tube above the obstruction so the spray clears it. That works well, but it adds hardware and reduces how easily you can pick the line up and move it. Maximum spray height is about 8 feet.

The Mark II sprays high and narrow. Its spray exits at a steep 80-degree angle — the water goes more up than out, reaching up to about 6.5 feet on each side for roughly 13 feet of total coverage. Maximum spray height is about 6.5 feet (2 meters) at full pressure. That steeper, more vertical pattern is the Mark II's defining advantage: because the spray arcs up and comes down from above, it clears taller crops that would block a low, flat R-Wide spray — without needing risers. Plenty of growers run the Mark II in the open field for exactly this reason, putting it on beds of trellised or tall crops where getting water up and over the canopy matters more than covering the widest possible block. It's also the natural fit for confined spaces where a 33-foot spray has nowhere to go.

So even setting pressure aside, the two tubes deliver water differently. The R-Wide blankets the widest area but stays low, so taller crops or covers mean adding risers. The Mark II covers less width but throws water up and over, clearing height without extra hardware.

This is where the two models sort themselves out for most growers.

The R-Wide is the wide-coverage field tube. Open ground, wide bed blocks, full sun, room for a 33-foot spray to spread without obstruction. This is what most market gardeners are buying it for, and it's where it shines. Ben Hartman covers his entire 15,000-square-foot field operation with five R-Wide lines. 

Jodi Roebuck redesigned his whole field layout into eight-bed blocks specifically to match the R-Wide's coverage width. When crops get tall or covers go on, growers keep the R-Wide working by raising it on risers.

The Mark II is the low-pressure, over-the-top tube. It earns its place in three situations. First, low water supply: its sub-3-PSI capability and small flow demand let it run off gravity tanks, rain barrels, and weak wells that can't power an R-Wide. Second, protected growing: in greenhouses and tunnels you usually have less width to cover and often lower pressure off a tank or sub-line, which suits it well. Third — and this is the one growers often overlook — taller field crops: the steep 80-degree spray throws water up and over the canopy, so you can irrigate trellised tomatoes, pole beans, or any tall planting in the open field without building risers. 

If your reason for looking past the R-Wide is crop height rather than water pressure, the Mark II is often the simpler answer.

Work through these three questions in order:

1. What's your water pressure? If you're working with a gravity tank, a rain barrel, or any low-pressure source under about 15 PSI, the Mark II is your tube — the R-Wide simply won't spray properly. If you have 15 PSI or more at the bed, the R-Wide is on the table.

2. How much flow can your source deliver? Measure your GPM (the Water Supply Check shows you how with a simple bucket test). Compare it to the tables above for the bed length you want to run. If your flow is limited, either shorten your runs or go with the lower-demand Mark II.

3. How tall are your crops, and where are you growing? Wide open blocks of low-profile crops point to the R-Wide. If you're growing tall or trellised crops, you have two options: keep the R-Wide and raise it on risers, or use the Mark II and let its steep spray clear the canopy on its own. Greenhouses, tunnels, and tight spaces also point to the Mark II.

For most market gardeners running open field beds of low crops with a reasonable water supply, the R-Wide is the answer — it's the workhorse of the lineup and covers the most ground per line, with risers available when crops get tall or covers go on. Reach for the Mark II when you're short on water pressure, growing under cover, or want to spray over taller crops without building risers.

When you're ready to size out exactly what you need — tube length, number of fittings, how many lines per block — our Sumi Soaker System Planner does the math for your specific layout. And if you're still on the fence between the two models after reading this, send us your water numbers and bed dimensions and we'll tell you which one fits.

Use our free online tools to get a personalized recommendation:

Sumi Soaker System Planner — Tells you what tubing and how many rolls you need based on your bed layout.

Sumi Soaker Water Supply Calculator — Tells you whether your water supply can handle the setup you need, and what to do if it can't.

Both tools are available at shop.moderngrower.co.

Questions? Email us or use the chat on our website. We'll walk you through it.

The Sumi Soaker R-Wide and Mark II are available in the US from Modern Grower. Visit shop.moderngrower.co to see the full product line, starter kits, and accessories.

Ready to figure out what you need? 

Use our System Planner to size your setup and our Water Supply Check to verify your pressure and flow. Or reach out to us directly at hello@moderngrower.co or 877.850.1555 — we're happy to help you design a system that fits your layout.