Poor toilet flush

Poor toilet flush issues, especially after a change of components, can arise due to several reasons. You mentioned that you previously had a Roca dual flush system, and from experience, Roca products have generally been robust. I recall that in a similar situation before, we used Roca products instead of opting for replacements. The choice of replacement can significantly impact the efficiency of the flush. The Fluidmaster you've now installed might not be compatible with the design or specifications of your toilet, hence affecting the flush power. It's essential to ensure that replacement parts match the original specifications, as this could lead to such discrepancies in performance. If you've already cleaned the jets and adjusted the water amount without seeing improvement, consider the following: Check the Chain: If the chain connecting the handle to the flapper is too slack or too tight, it might not be lifting the flapper high enough or for long enough to allow a full volume of water to flow from the tank to the bowl. Inspect the Fill Valve: Ensure that the fill valve is functioning correctly. If it's not filling the tank to its proper level, you won't get a strong flush. Adjust the float to increase the water level if necessary. Compatibility: Some toilets are designed explicitly with specific flush mechanisms in mind. Reverting back to a Roca system or consulting with the manufacturer for recommended replacements might resolve the issue. Seals and Gaskets: Ensure that all seals and gaskets have been correctly placed and are not obstructing the flow of water. Professional Insight: Sometimes, nuances in installations can be missed by homeowners but easily spotted by a professional. Consider getting a second opinion from another plumber or reaching out to the manufacturer for advice. In any case, based on past experience, it might be worthwhile to consider re-installing a Roca product if that's what worked best with your toilet model. They tend to be reliable and efficient, and ensuring the flush system is compatible with the toilet design is crucial for optimal performance.

There is a restricter in the replacement fluidmaster to restrict the pressure. It can be removed.

Not enough info. If it's a top mounted dual flush button on a close coupled wc and pan, the flush 'stalks' can be adjusted. Photo would help.