For the building in BMC, see Bloontonium Generator.
Activate submerge using target option to detect camo, pop bloons, and reduce water tower cooldowns 15% (doesn't stack).
~ Description from BTD5 Mobile
Submerge to detect Camo, pop Bloons and reduce ability cooldowns of nearby water-based Monkeys by 15%.
~ Description from BTD6

Bloontonium Reactor (sometimes shortened to Reactor or Reactor Sub) is the fourth upgrade on path one for the Monkey Sub in BTD6. It allows the sub to reveal Camo Bloons, in the same way as Submerge and Support, but when submerged, it will also pop bloons within its radius. As a bonus, it reduces water tower ability cooldowns (First Strike Capability and Monkey Pirates, as well as the Pirate Lord ability) by 15% if they are within its radius. It should be noted that while the cooldown bonus does not stack with other Bloontonium Reactors, it will still stack with High Energy Beacon and Hotter Cooldown (85% total if hotter cooldown is fully upgraded, or 65% total on BTD5 Flash with the premium upgrade). In BTD6, this upgrade also blocks Regrowth in its range, similar to the Monkey Village's Grow Blocker upgrade.

Mechanics (BTD6)Edit

  • While the decamo effect has infinite pierce, the radioactive attack has a pierce of 70.
  • The submerged Sub's attack does not stack with other Subs in the radius. The exact mechanic preventing this is unknown.
  • If switching between Submerge and another targeting option at correct speeds, the Bloontonium Reactor can apply both attacks, increasing the overall DPS of the Reactor.
  • Submerging a Bloontonium Reactor has a very quick decamo rate; it decamos bloons in range every 0.3 seconds, enough to decamo virtually any bloon passing by.
  • A submerged Bloontonium Reactor can decamo an infinite amount of bloons per decamo pulse.


  • Using the Reactor to decrease ability cooldown of First Strike Capability allows for an easier double First Strike activation, especially on shorter maps or where the First Strike can only be bought very late.
  • Do note that using the Reactor as your main decamo tower may have issues on Round 100, where the BAD can pop at an unfavourable spot releasing DDTs that are not decamoised.

Update History (BTD6)Edit


Buff Bloontonium Reactor pierce increased (30 → 70).

  • Buff Bloontonium Reactor has more range (50 --> 52)
  • Buff 4-0-1 Submerge and Support Sub gains increased damage pulse rate (0.3s -> 0.255s)
  • Buff 4-0-2 Submerge and Support Sub gains increased damage pulse rate (0.3s -> 0.19125s)
  • Buff 4-1-0 Submerged Reactor Sub gains 20% increased pierce from 70 -> 84
  • Buff 4-2-0 Submerged Reactor Sub deals +1 damage to Leads

Update History (Bloons TD Battles Mobile)Edit


Nerf Bloontonium Reactor price increased ($2500 → $2800).


Buff Bloontonium Reactor now automatically switches the tower into submerged mode upon purchase.


Nerf Fixed a bug where Bloontonium Reactor's water tower cooldown decrease stacked with any other Reactor in range



  • In BTD5, this is one of the few upgrades that has infinite popping power.
    • In BTD6 it has been nerfed to only pop up to 30 bloons per pulse.
      • However, in version 2.0, the upgrade has been buffed to pop up to 70 bloons per pulse.
  • A submerged Bloontonium Reactor acts like a Ring of Fire, but it is used on water and it has Camo Bloon detection, as well as reducing the cooldown of nearby water towers.
  • In Bloons TD Battles, with a regular defense, it can stop a Rainbow Bloon rush.
  • In BTD5 Flash, multiple Bloontonium Reactors placed close to each other can stack their popping power, and 2 to 3 of them can stop even a full Regrow Ceramic if placed precisely.
    • In Mobile, Bloontonium Reactors popping power does not stack.
  • In BTD5 Mobile, the Bloontonium Reactor has sailplanes. On the web version, however, this is not true.
  • If you look closely, the boat looks like a Los Angeles class nuclear attack submarine.
  • In BTD5-era games, although the description says that the cooldown reduction does not stack, it actually does stack with multiple subs, which can further decrease the ability cooldowns. Thus, using at least seven of these will fully cancel the ability cooldown, allowing for hypersonic abilities. In BMC Mobile, this exploit is incredibly useful for reaching high rounds in Contested Territory if the current map is set on Lake or River Terrain and First Strike Capability is used, allowing the player to take out even strong Z.O.M.G.s very quickly and easily. The same thing is true when fighting Bloonarius.
    • This was fixed in BTD Battles Mobile, preventing the ability cooldown reductions from stacking.
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