Description
Hanna Instruments Suction filter for BL121 (BL120-200)
Nothing is more annoying than a dosing system that suddenly stops working because the line is clogged. Often, the cause is sediment at the bottom of your bottle: small particles and residue that are slowly sucked up and clog the thin suction hose. This suction filter from Hanna Instruments (item number BL120-200) solves exactly that problem by keeping the debris out before it can reach your system.
Place the filter in the bottle at the end of the suction line. This ensures that your controller only draws in clean liquid, while the settled debris stays neatly at the bottom. The result: fewer malfunctions, more stable dosing, and less hassle with maintenance.
Why a weighted filter makes all the difference
This suction filter is equipped with a ceramic weight. That may seem like a small detail, but it’s essential: the weight pulls the filter to the bottom and keeps it there, even as the liquid level in the bottle drops. This allows you to continue drawing liquid right down to the last few centimeters, ensuring you get the most out of your reservoir. Without the weight, the hose would float, and at some point, you’d end up sucking in air instead of your product.
Fits standard 6 × 4 mm hose
The filter is designed for the standard 6 × 4 mm suction line and connects to it seamlessly. It was originally developed for the Hanna BL121 and BL122 controllers from the Security Pool Plus series, but it also fits other BL10x, BL12x, and BL13x dosing systems that use the same pipe size. Not sure if this is the right one for your setup? Just check the hose diameter—that’s the deciding factor.
Installation and Replacement
Installation is simple: first slide the ceramic weight over the hose, followed by the compression fitting. Then place the end of the hose onto the filter and tighten the compression fitting onto the filter. To replace the filter, remove the old one, rinse everything thoroughly in a bucket of water, cut off the first meter of the suction line, and install the new filter. Be sure to wear protective clothing, especially when working with pH or chlorine products.
It pays to replace it annually
I recommend replacing the suction filter every year. A filter that becomes clogged loses its effectiveness and will eventually allow debris to pass through. For just a few euros, you can prevent costly malfunctions and keep your pH/ORP dosing system running reliably. At Pool.shop, we’re happy to help if you’re not sure exactly which part you need.
