Food Not Dispensing — Troubleshooting GuideUpdated a month ago

If your aF4 is running its feed cycle but little or no food is reaching your aquarium, this guide will help you identify and fix the cause. Most dispensing issues are related to food preparation or tubing placement and can be resolved quickly without contacting support.

Step 1 — Check tubing placement

Incorrect intake tubing placement is the most common causes of dispensing failure. Because the reservoir is typically already filled with slurry when the tube is inserted, it is easy to accidentally place the tube directly over one of the prongs inside the reservoir without realizing it — the slurry makes it impossible to see what's happening at the bottom.

A tube resting over a prong will be partially or fully obstructed, restricting food flow significantly.

How this issue presents:

Dilution water runs out faster than the food
Dried food is left behind in the reservoir after feed cycles
Food output is reduced or inconsistent

The correct way to seat the tubing:

Insert the intake tube into the reservoir before loading any food or slurry so you can see the prongs clearly
Position the tube so it sits centered between the prongs — not over any of them
Press the tube fully down until it is seated
Gently pull the tube back approximately ¼ inch — this prevents the tube from being compressed at the exit point of the reservoir

If your reservoir is already loaded, carefully remove the tube, inspect its position, reload it correctly using the steps above, and run a Feed Now cycle to test.

Step 2 — Check slurry consistency

Food that is too thick will not flow through the tubing reliably and is also a common cause of reduced or inconsistent output.

The fix: When loading the reservoir, always add dilution water up to the max fill line before closing the lid. This ensures the correct slurry consistency for reliable dispensing throughout the entire reservoir load.

For full guidance on correct dilution ratios see our Slurry Dilution Guide.

Step 3 — Check for frozen food in the reservoir

This issue most commonly occurs when users load frozen food cubes directly into the aF4 on the snowflake (coldest) setting without first allowing them to thaw into slurry form. The cubes freeze together into a solid mass rather than remaining as a pourable slurry, blocking the intake tube.

It can also occur when dilution water salinity is too low, which raises the freezing point of the slurry and causes it to freeze at temperatures that would otherwise be safe.

How to check: Open the reservoir lid and inspect the food. If it has frozen solid rather than remaining as a pourable slurry, one of the causes above is likely.

The fix — try these in order:

Allow cubes to thaw into slurry before loading — never load frozen cubes directly into a cold reservoir. Let them thaw to slurry consistency first, then load.
Use higher salinity dilution water — low salinity dilution raises the freezing point of the mixture. Use high salinity saltwater to keep the slurry at the right consistency.
Try temperature setting 2 instead of the snowflake setting — every unit is individually calibrated and some run slightly colder than others. Setting 2 maintains excellent food freshness and in cases where step 1/2 did not resolve the issue, it will be as effective as the snowflake setting, with more consistent results across different food types and dilution ratios.

For temperature setting guidance see our Temperature Settings Guide.

Step 4 — Check food type and particle size

The aF4 is designed to dispense cube-based frozen foods such as mysis shrimp and brine shrimp when properly prepared as a slurry. Foods with large particles — such as clam, squid, and mussel, most commonly found in predator mix sheet foods — can restrict or block the tubing if not broken down adequately before loading.

If you are using sheet food or predator mix foods: Ensure the food has been fully prepared according to our Sheet Food Preparation Guide before loading. Inadequately broken down sheet food is a common cause of reduced flow that can be difficult to clear without removing the tubing.

Step 5 — If flow issues persist after all of the above

If you have confirmed correct tubing placement, correct slurry consistency, no frozen solid food, and appropriate food preparation — and the aF4 is still not dispensing correctly — run an Auto-Clean cycle.

Run an Auto-Clean cycleThe aF4's auto-clean function flushes the system and can resolve minor flow restrictions. Activate it from the main UI. Auto-clean should only be run with the output tube directed away from the aquarium.

If the Auto-Clean cycle does not resolve the issue:Persistent dispensing failure after all of the above checks most likely indicates a solenoid issue. See our Solenoid Failure Guide for symptoms and next steps.

If you would like to investigate the tubing further, see our Tubing Replacement Guide — note that this is an advanced procedure and is unlikely to be the cause of dispensing issues if you have worked through all steps above.

Quick reference

Symptom	Most likely cause	Fix
Dilution runs out faster than food, dried food in reservoir	Tube over a prong	Re-seat tubing before loading
Reduced or inconsistent output	Slurry too thick	Fill to max line with dilution water
Food frozen solid in reservoir	Loaded frozen, low salinity, or snowflake setting	Thaw first, higher salinity, try setting 2
Flow restricted with predator mix or sheet food	Particle size too large	Review sheet food preparation guide
Passes all checks, still not dispensing	Solenoid issue	See solenoid failure guide

Slurry Dilution Guide — correct dilution for reliable dispensing
Temperature Settings Guide — avoiding frozen food in the reservoir
Sheet Food Preparation Guide — preparing large particle foods correctly
Solenoid Failure Guide — if dispensing issues persist after all checks
Tubing Replacement Guide — advanced tubing inspection and replacement

Still having issues? Submit a ticket and our team will help you get it sorted.

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